diff --git a/go/demo_eventticket.go b/go/demo_eventticket.go
index ecc31d5..b4d2ed1 100644
--- a/go/demo_eventticket.go
+++ b/go/demo_eventticket.go
@@ -20,6 +20,7 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"github.com/golang-jwt/jwt"
@@ -27,35 +28,34 @@ import (
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	oauthJwt "golang.org/x/oauth2/jwt"
+	"google.golang.org/api/option"
+	"google.golang.org/api/walletobjects/v1"
 	"io"
-	"net/http"
+	"log"
 	"os"
 	"strings"
 )
 
 // [END imports]
-
-const (
-	batchUrl  = "https://walletobjects.googleapis.com/batch"
-	classUrl  = "https://walletobjects.googleapis.com/walletobjects/v1/eventTicketClass"
-	objectUrl = "https://walletobjects.googleapis.com/walletobjects/v1/eventTicketObject"
-)
-
 // [END setup]
 
 type demoEventticket struct {
-	credentials                   *oauthJwt.Config
-	httpClient                    *http.Client
-	batchUrl, classUrl, objectUrl string
+	credentials *oauthJwt.Config
+	service     *walletobjects.Service
 }
 
 // [START auth]
 // Create authenticated HTTP client using a service account file.
 func (d *demoEventticket) auth() {
-	b, _ := os.ReadFile(os.Getenv("GOOGLE_APPLICATION_CREDENTIALS"))
-	credentials, _ := google.JWTConfigFromJSON(b, "https://www.googleapis.com/auth/wallet_object.issuer")
+	credentialsFile := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
+	b, _ := os.ReadFile(credentialsFile)
+	credentials, err := google.JWTConfigFromJSON(b, walletobjects.WalletObjectIssuerScope)
+	if err != nil {
+		fmt.Println(err)
+		log.Fatalf("Unable to load credentials: %v", err)
+	}
 	d.credentials = credentials
-	d.httpClient = d.credentials.Client(oauth2.NoContext)
+	d.service, _ = walletobjects.NewService(context.Background(), option.WithCredentialsFile(credentialsFile))
 }
 
 // [END auth]
@@ -63,28 +63,21 @@ func (d *demoEventticket) auth() {
 // [START createClass]
 // Create a class.
 func (d *demoEventticket) createClass(issuerId, classSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"eventId": "EVENT_ID",
-		"eventName": {
-			"defaultValue": {
-				"value": "Event name",
-				"language": "en-US"
-			}
+	eventticketClass := new(walletobjects.EventTicketClass)
+	eventticketClass.Id = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	eventticketClass.EventName = &walletobjects.LocalizedString{
+		DefaultValue: &walletobjects.TranslatedString{
+			Language: "en-us",
+			Value:    "Event name",
 		},
-		"issuerName": "Issuer name",
-		"id": "%s.%s",
-		"reviewStatus": "UNDER_REVIEW"
 	}
-	`, issuerId, classSuffix)
-
-	res, err := d.httpClient.Post(classUrl, "application/json", bytes.NewBuffer([]byte(newClass)))
-
+	eventticketClass.IssuerName = "Issuer name"
+	eventticketClass.ReviewStatus = "UNDER_REVIEW"
+	res, err := d.service.Eventticketclass.Insert(eventticketClass).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert class: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Class insert response:\n%s\n", b)
+		fmt.Printf("Class insert id:\n%v\n", res.Id)
 	}
 }
 
@@ -93,107 +86,90 @@ func (d *demoEventticket) createClass(issuerId, classSuffix string) {
 // [START createObject]
 // Create an object.
 func (d *demoEventticket) createObject(issuerId, classSuffix, objectSuffix string) {
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"ticketHolderName": "Ticket holder name",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
+	eventticketObject := new(walletobjects.EventTicketObject)
+	eventticketObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	eventticketObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	eventticketObject.TicketHolderName = "Ticket holder name"
+	eventticketObject.TicketNumber = "Ticket number"
+	eventticketObject.State = "ACTIVE"
+	eventticketObject.HeroImage = &walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
+			Uri: "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg",
+		},
+	}
+	eventticketObject.Barcode = &walletobjects.Barcode{
+		Type:  "QR_CODE",
+		Value: "QR code",
+	}
+	eventticketObject.Locations = []*walletobjects.LatLongPoint{
+		&walletobjects.LatLongPoint{
+			Latitude:  37.424015499999996,
+			Longitude: -122.09259560000001,
+		},
+	}
+	eventticketObject.LinksModuleData = &walletobjects.LinksModuleData{
+		Uris: []*walletobjects.Uri{
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_URI_ID",
+				Uri:         "http://maps.google.com/",
+				Description: "Link module URI description",
+			},
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_TEL_ID",
+				Uri:         "tel:6505555555",
+				Description: "Link module tel description",
+			},
+		},
+	}
+	eventticketObject.ImageModulesData = []*walletobjects.ImageModuleData{
+		&walletobjects.ImageModuleData{
+			Id: "IMAGE_MODULE_ID",
+			MainImage: &walletobjects.Image{
+				SourceUri: &walletobjects.ImageUri{
+					Uri: "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg",
+				},
+			},
+		},
+	}
+	eventticketObject.TextModulesData = []*walletobjects.TextModuleData{
+		&walletobjects.TextModuleData{
+			Body:   "Text module body",
+			Header: "Text module header",
+			Id:     "TEXT_MODULE_ID",
+		},
+	}
+	eventticketObject.SeatInfo = &walletobjects.EventSeat{
+		Gate: &walletobjects.LocalizedString{
+			DefaultValue: &walletobjects.TranslatedString{
+				Language: "en-us",
+				Value:    "A",
+			},
+		},
+		Section: &walletobjects.LocalizedString{
+			DefaultValue: &walletobjects.TranslatedString{
+				Language: "en-us",
+				Value:    "5",
+			},
+		},
+		Row: &walletobjects.LocalizedString{
+			DefaultValue: &walletobjects.TranslatedString{
+				Language: "en-us",
+				Value:    "G3",
+			},
+		},
+		Seat: &walletobjects.LocalizedString{
+			DefaultValue: &walletobjects.TranslatedString{
+				Language: "en-us",
+				Value:    "42",
+			},
 		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"ticketNumber": "Ticket number",
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"seatInfo": {
-			"gate": {
-				"defaultValue": {
-					"value": "A",
-					"language": "en-US"
-				}
-			},
-			"section": {
-				"defaultValue": {
-					"value": "5",
-					"language": "en-US"
-				}
-			},
-			"row": {
-				"defaultValue": {
-					"value": "G3",
-					"language": "en-US"
-				}
-			},
-			"seat": {
-				"defaultValue": {
-					"value": "42",
-					"language": "en-US"
-				}
-			}
-		},
-		"id": "%s.%s"
 	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	res, err := d.httpClient.Post(objectUrl, "application/json", bytes.NewBuffer([]byte(newObject)))
 
+	res, err := d.service.Eventticketobject.Insert(eventticketObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object insert response:\n%s\n", b)
+		fmt.Printf("Object insert id:\n%s\n", res.Id)
 	}
 }
 
@@ -205,16 +181,14 @@ func (d *demoEventticket) createObject(issuerId, classSuffix, objectSuffix strin
 // Sets the object's state to Expired. If the valid time interval is
 // already set, the pass will expire automatically up to 24 hours after.
 func (d *demoEventticket) expireObject(issuerId, objectSuffix string) {
-	patchBody := `{"state": "EXPIRED"}`
-	url := fmt.Sprintf("%s/%s.%s", objectUrl, issuerId, objectSuffix)
-	req, _ := http.NewRequest(http.MethodPatch, url, bytes.NewBuffer([]byte(patchBody)))
-	res, err := d.httpClient.Do(req)
-
+	eventticketObject := &walletobjects.EventTicketObject{
+		State: "EXPIRED",
+	}
+	res, err := d.service.Eventticketobject.Patch(fmt.Sprintf("%s.%s", issuerId, objectSuffix), eventticketObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to patch object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object expiration response:\n%s\n", b)
+		fmt.Printf("Object expiration id:\n%s\n", res.Id)
 	}
 }
 
@@ -228,123 +202,20 @@ func (d *demoEventticket) expireObject(issuerId, objectSuffix string) {
 // created. This allows you to create multiple pass classes and objects in
 // one API call when the user saves the pass to their wallet.
 func (d *demoEventticket) createJwtNewObjects(issuerId, classSuffix, objectSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"eventId": "EVENT_ID",
-		"eventName": {
-			"defaultValue": {
-				"value": "Event name",
-				"language": "en-US"
-			}
-		},
-		"issuerName": "Issuer name",
-		"id": "%s.%s",
-		"reviewStatus": "UNDER_REVIEW"
-	}
-	`, issuerId, classSuffix)
+	eventticketObject := new(walletobjects.EventTicketObject)
+	eventticketObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	eventticketObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	eventticketObject.TicketHolderName = "Ticket holder name"
+	eventticketObject.TicketNumber = "Ticket number"
+	eventticketObject.State = "ACTIVE"
 
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"ticketHolderName": "Ticket holder name",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"ticketNumber": "Ticket number",
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"seatInfo": {
-			"gate": {
-				"defaultValue": {
-					"value": "A",
-					"language": "en-US"
-				}
-			},
-			"section": {
-				"defaultValue": {
-					"value": "5",
-					"language": "en-US"
-				}
-			},
-			"row": {
-				"defaultValue": {
-					"value": "G3",
-					"language": "en-US"
-				}
-			},
-			"seat": {
-				"defaultValue": {
-					"value": "42",
-					"language": "en-US"
-				}
-			}
-		},
-		"id": "%s.%s"
-	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	var payload map[string]interface{}
+	eventticketJson, _ := json.Marshal(eventticketObject)
+	var payload map[string]any
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
-		"genericClasses": [%s],
-		"genericObjects": [%s]
+		"eventticketObjects": [%s]
 	}
-	`, newClass, newObject)), &payload)
-
+	`, eventticketJson)), &payload)
 	claims := jwt.MapClaims{
 		"iss":     d.credentials.Email,
 		"aud":     "google",
@@ -370,7 +241,7 @@ func (d *demoEventticket) createJwtNewObjects(issuerId, classSuffix, objectSuffi
 // their wallet, the pass objects defined in the JWT are added to the
 // user's Google Wallet app. This allows the user to save multiple pass
 // objects in one API call.
-func (d *demoEventticket) createJwtExistingObjects(issuerId string) {
+func (d *demoEventticket) createJwtExistingObjects(issuerId string, classSuffix string, objectSuffix string) {
 	var payload map[string]interface{}
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
@@ -394,7 +265,7 @@ func (d *demoEventticket) createJwtExistingObjects(issuerId string) {
 			"classId": "%s.GIFT_CARD_CLASS_SUFFIX"
 		}],
 
-		"loyaltyObjects": [{
+		"eventticketObjects": [{
 			"id": "%s.LOYALTY_OBJECT_SUFFIX",
 			"classId": "%s.LOYALTY_CLASS_SUFFIX"
 		}],
@@ -436,99 +307,15 @@ func (d *demoEventticket) batchCreateObjects(issuerId, classSuffix string) {
 	for i := 0; i < 3; i++ {
 		objectSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 
-		batchObject := fmt.Sprintf(`
-		{
-			"classId": "%s.%s",
-			"ticketHolderName": "Ticket holder name",
-			"heroImage": {
-				"contentDescription": {
-					"defaultValue": {
-						"value": "Hero image description",
-						"language": "en-US"
-					}
-				},
-				"sourceUri": {
-					"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-				}
-			},
-			"barcode": {
-				"type": "QR_CODE",
-				"value": "QR code"
-			},
-			"locations": [
-				{
-					"latitude": 37.424015499999996,
-					"longitude": -122.09259560000001
-				}
-			],
-			"state": "ACTIVE",
-			"linksModuleData": {
-				"uris": [
-					{
-						"id": "LINK_MODULE_URI_ID",
-						"uri": "http://maps.google.com/",
-						"description": "Link module URI description"
-					},
-					{
-						"id": "LINK_MODULE_TEL_ID",
-						"uri": "tel:6505555555",
-						"description": "Link module tel description"
-					}
-				]
-			},
-			"ticketNumber": "Ticket number",
-			"imageModulesData": [
-				{
-					"id": "IMAGE_MODULE_ID",
-					"mainImage": {
-						"contentDescription": {
-							"defaultValue": {
-								"value": "Image module description",
-								"language": "en-US"
-							}
-						},
-						"sourceUri": {
-							"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-						}
-					}
-				}
-			],
-			"textModulesData": [
-				{
-					"body": "Text module body",
-					"header": "Text module header",
-					"id": "TEXT_MODULE_ID"
-				}
-			],
-			"seatInfo": {
-				"gate": {
-					"defaultValue": {
-						"value": "A",
-						"language": "en-US"
-					}
-				},
-				"section": {
-					"defaultValue": {
-						"value": "5",
-						"language": "en-US"
-					}
-				},
-				"row": {
-					"defaultValue": {
-						"value": "G3",
-						"language": "en-US"
-					}
-				},
-				"seat": {
-					"defaultValue": {
-						"value": "42",
-						"language": "en-US"
-					}
-				}
-			},
-			"id": "%s.%s"
-		}
-		`, issuerId, classSuffix, issuerId, objectSuffix)
+		eventticketObject := new(walletobjects.EventTicketObject)
+		eventticketObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+		eventticketObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+		eventticketObject.TicketHolderName = "Ticket holder name"
+		eventticketObject.TicketNumber = "Ticket number"
+		eventticketObject.State = "ACTIVE"
+
+		eventticketJson, _ := json.Marshal(eventticketObject)
+		batchObject := fmt.Sprintf("%s", eventticketJson)
 
 		data += "--batch_createobjectbatch\n"
 		data += "Content-Type: application/json\n\n"
@@ -537,9 +324,7 @@ func (d *demoEventticket) batchCreateObjects(issuerId, classSuffix string) {
 	}
 	data += "--batch_createobjectbatch--"
 
-
-	// batchUrl = 'https://walletobjects.googleapis.com/batch';
-	res, err := d.httpClient.Post(batchUrl, "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
+	res, err := d.credentials.Client(oauth2.NoContext).Post("https://walletobjects.googleapis.com/batch", "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
 
 	if err != nil {
 		fmt.Println(err)
@@ -552,11 +337,6 @@ func (d *demoEventticket) batchCreateObjects(issuerId, classSuffix string) {
 // [END batch]
 
 func main() {
-	if len(os.Args) == 0 {
-		fmt.Println("Usage: go run demo_eventticket.go <issuer-id>")
-		os.Exit(1)
-	}
-
 	issuerId := os.Getenv("WALLET_ISSUER_ID")
 	classSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 	objectSuffix := fmt.Sprintf("%s-%s", strings.ReplaceAll(uuid.New().String(), "-", "_"), classSuffix)
@@ -568,6 +348,6 @@ func main() {
 	d.createObject(issuerId, classSuffix, objectSuffix)
 	d.expireObject(issuerId, objectSuffix)
 	d.createJwtNewObjects(issuerId, classSuffix, objectSuffix)
-	d.createJwtExistingObjects(issuerId)
+	d.createJwtExistingObjects(issuerId, classSuffix, objectSuffix)
 	d.batchCreateObjects(issuerId, classSuffix)
 }
diff --git a/go/demo_flight.go b/go/demo_flight.go
index d1a45e9..8707d51 100644
--- a/go/demo_flight.go
+++ b/go/demo_flight.go
@@ -20,6 +20,7 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"github.com/golang-jwt/jwt"
@@ -27,35 +28,34 @@ import (
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	oauthJwt "golang.org/x/oauth2/jwt"
+	"google.golang.org/api/option"
+	"google.golang.org/api/walletobjects/v1"
 	"io"
-	"net/http"
+	"log"
 	"os"
 	"strings"
 )
 
 // [END imports]
-
-const (
-	batchUrl  = "https://walletobjects.googleapis.com/batch"
-	classUrl  = "https://walletobjects.googleapis.com/walletobjects/v1/flightClass"
-	objectUrl = "https://walletobjects.googleapis.com/walletobjects/v1/flightObject"
-)
-
 // [END setup]
 
 type demoFlight struct {
-	credentials                   *oauthJwt.Config
-	httpClient                    *http.Client
-	batchUrl, classUrl, objectUrl string
+	credentials *oauthJwt.Config
+	service     *walletobjects.Service
 }
 
 // [START auth]
 // Create authenticated HTTP client using a service account file.
 func (d *demoFlight) auth() {
-	b, _ := os.ReadFile(os.Getenv("GOOGLE_APPLICATION_CREDENTIALS"))
-	credentials, _ := google.JWTConfigFromJSON(b, "https://www.googleapis.com/auth/wallet_object.issuer")
+	credentialsFile := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
+	b, _ := os.ReadFile(credentialsFile)
+	credentials, err := google.JWTConfigFromJSON(b, walletobjects.WalletObjectIssuerScope)
+	if err != nil {
+		fmt.Println(err)
+		log.Fatalf("Unable to load credentials: %v", err)
+	}
 	d.credentials = credentials
-	d.httpClient = d.credentials.Client(oauth2.NoContext)
+	d.service, _ = walletobjects.NewService(context.Background(), option.WithCredentialsFile(credentialsFile))
 }
 
 // [END auth]
@@ -63,38 +63,33 @@ func (d *demoFlight) auth() {
 // [START createClass]
 // Create a class.
 func (d *demoFlight) createClass(issuerId, classSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"origin": {
-			"terminal": "1",
-			"gate": "A2",
-			"airportIataCode": "LAX"
-		},
-		"flightHeader": {
-			"carrier": {
-				"carrierIataCode": "LX"
-			},
-			"flightNumber": "123"
-		},
-		"localScheduledDepartureDateTime": "2023-07-02T15:30:00",
-		"reviewStatus": "UNDER_REVIEW",
-		"issuerName": "Issuer name",
-		"destination": {
-			"terminal": "2",
-			"gate": "C3",
-			"airportIataCode": "SFO"
-		},
-		"id": "%s.%s"
+	flightClass := new(walletobjects.FlightClass)
+	flightClass.Id = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	flightClass.ReviewStatus = "UNDER_REVIEW"
+	flightClass.IssuerName = "Issuer name"
+	flightClass.Origin = &walletobjects.AirportInfo{
+		Terminal:        "1",
+		Gate:            "A2",
+		AirportIataCode: "LAX",
 	}
-	`, issuerId, classSuffix)
-
-	res, err := d.httpClient.Post(classUrl, "application/json", bytes.NewBuffer([]byte(newClass)))
+	flightClass.Destination = &walletobjects.AirportInfo{
+		Terminal:        "2",
+		Gate:            "C3",
+		AirportIataCode: "SFO",
+	}
+	flightClass.FlightHeader = &walletobjects.FlightHeader{
+		Carrier: &walletobjects.FlightCarrier{
+			CarrierIataCode: "LX",
+		},
+		FlightNumber: "123",
+	}
+	flightClass.LocalScheduledDepartureDateTime = "2023-06-12T23:20:50"
 
+	res, err := d.service.Flightclass.Insert(flightClass).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert class: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Class insert response:\n%s\n", b)
+		fmt.Printf("Class insert id:\n%v\n", res.Id)
 	}
 }
 
@@ -103,87 +98,70 @@ func (d *demoFlight) createClass(issuerId, classSuffix string) {
 // [START createObject]
 // Create an object.
 func (d *demoFlight) createObject(issuerId, classSuffix, objectSuffix string) {
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"passengerName": "Passenger name",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"boardingAndSeatingInfo": {
-			"boardingGroup": "B",
-			"seatNumber": "42"
-		},
-		"reservationInfo": {
-			"confirmationCode": "Confirmation code"
-		},
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"id": "%s.%s"
+	flightObject := new(walletobjects.FlightObject)
+	flightObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	flightObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	flightObject.State = "ACTIVE"
+	flightObject.PassengerName = "Passenger name"
+	flightObject.ReservationInfo = &walletobjects.ReservationInfo{
+		ConfirmationCode: "Confirmation code",
+	}
+	flightObject.BoardingAndSeatingInfo = &walletobjects.BoardingAndSeatingInfo{
+		BoardingGroup: "B",
+		SeatNumber:    "42",
+	}
+	flightObject.HeroImage = &walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
+			Uri: "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg",
+		},
+	}
+	flightObject.Barcode = &walletobjects.Barcode{
+		Type:  "QR_CODE",
+		Value: "QR code",
+	}
+	flightObject.Locations = []*walletobjects.LatLongPoint{
+		&walletobjects.LatLongPoint{
+			Latitude:  37.424015499999996,
+			Longitude: -122.09259560000001,
+		},
+	}
+	flightObject.LinksModuleData = &walletobjects.LinksModuleData{
+		Uris: []*walletobjects.Uri{
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_URI_ID",
+				Uri:         "http://maps.google.com/",
+				Description: "Link module URI description",
+			},
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_TEL_ID",
+				Uri:         "tel:6505555555",
+				Description: "Link module tel description",
+			},
+		},
+	}
+	flightObject.ImageModulesData = []*walletobjects.ImageModuleData{
+		&walletobjects.ImageModuleData{
+			Id: "IMAGE_MODULE_ID",
+			MainImage: &walletobjects.Image{
+				SourceUri: &walletobjects.ImageUri{
+					Uri: "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg",
+				},
+			},
+		},
+	}
+	flightObject.TextModulesData = []*walletobjects.TextModuleData{
+		&walletobjects.TextModuleData{
+			Body:   "Text module body",
+			Header: "Text module header",
+			Id:     "TEXT_MODULE_ID",
+		},
 	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	res, err := d.httpClient.Post(objectUrl, "application/json", bytes.NewBuffer([]byte(newObject)))
 
+	res, err := d.service.Flightobject.Insert(flightObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object insert response:\n%s\n", b)
+		fmt.Printf("Object insert id:\n%s\n", res.Id)
 	}
 }
 
@@ -195,16 +173,14 @@ func (d *demoFlight) createObject(issuerId, classSuffix, objectSuffix string) {
 // Sets the object's state to Expired. If the valid time interval is
 // already set, the pass will expire automatically up to 24 hours after.
 func (d *demoFlight) expireObject(issuerId, objectSuffix string) {
-	patchBody := `{"state": "EXPIRED"}`
-	url := fmt.Sprintf("%s/%s.%s", objectUrl, issuerId, objectSuffix)
-	req, _ := http.NewRequest(http.MethodPatch, url, bytes.NewBuffer([]byte(patchBody)))
-	res, err := d.httpClient.Do(req)
-
+	flightObject := &walletobjects.FlightObject{
+		State: "EXPIRED",
+	}
+	res, err := d.service.Flightobject.Patch(fmt.Sprintf("%s.%s", issuerId, objectSuffix), flightObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to patch object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object expiration response:\n%s\n", b)
+		fmt.Printf("Object expiration id:\n%s\n", res.Id)
 	}
 }
 
@@ -218,113 +194,22 @@ func (d *demoFlight) expireObject(issuerId, objectSuffix string) {
 // created. This allows you to create multiple pass classes and objects in
 // one API call when the user saves the pass to their wallet.
 func (d *demoFlight) createJwtNewObjects(issuerId, classSuffix, objectSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"origin": {
-			"terminal": "1",
-			"gate": "A2",
-			"airportIataCode": "LAX"
-		},
-		"flightHeader": {
-			"carrier": {
-				"carrierIataCode": "LX"
-			},
-			"flightNumber": "123"
-		},
-		"localScheduledDepartureDateTime": "2023-07-02T15:30:00",
-		"reviewStatus": "UNDER_REVIEW",
-		"issuerName": "Issuer name",
-		"destination": {
-			"terminal": "2",
-			"gate": "C3",
-			"airportIataCode": "SFO"
-		},
-		"id": "%s.%s"
+	flightObject := new(walletobjects.FlightObject)
+	flightObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	flightObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	flightObject.State = "ACTIVE"
+	flightObject.PassengerName = "Passenger name"
+	flightObject.ReservationInfo = &walletobjects.ReservationInfo{
+		ConfirmationCode: "Confirmation code",
 	}
-	`, issuerId, classSuffix)
 
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"passengerName": "Passenger name",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"boardingAndSeatingInfo": {
-			"boardingGroup": "B",
-			"seatNumber": "42"
-		},
-		"reservationInfo": {
-			"confirmationCode": "Confirmation code"
-		},
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"id": "%s.%s"
-	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	var payload map[string]interface{}
+	flightJson, _ := json.Marshal(flightObject)
+	var payload map[string]any
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
-		"genericClasses": [%s],
-		"genericObjects": [%s]
+		"flightObjects": [%s]
 	}
-	`, newClass, newObject)), &payload)
-
+	`, flightJson)), &payload)
 	claims := jwt.MapClaims{
 		"iss":     d.credentials.Email,
 		"aud":     "google",
@@ -350,7 +235,7 @@ func (d *demoFlight) createJwtNewObjects(issuerId, classSuffix, objectSuffix str
 // their wallet, the pass objects defined in the JWT are added to the
 // user's Google Wallet app. This allows the user to save multiple pass
 // objects in one API call.
-func (d *demoFlight) createJwtExistingObjects(issuerId string) {
+func (d *demoFlight) createJwtExistingObjects(issuerId string, classSuffix string, objectSuffix string) {
 	var payload map[string]interface{}
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
@@ -379,7 +264,7 @@ func (d *demoFlight) createJwtExistingObjects(issuerId string) {
 			"classId": "%s.LOYALTY_CLASS_SUFFIX"
 		}],
 
-		"offerObjects": [{
+		"flightObjects": [{
 			"id": "%s.OFFER_OBJECT_SUFFIX",
 			"classId": "%s.OFFER_CLASS_SUFFIX"
 		}],
@@ -416,79 +301,17 @@ func (d *demoFlight) batchCreateObjects(issuerId, classSuffix string) {
 	for i := 0; i < 3; i++ {
 		objectSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 
-		batchObject := fmt.Sprintf(`
-		{
-			"classId": "%s.%s",
-			"passengerName": "Passenger name",
-			"heroImage": {
-				"contentDescription": {
-					"defaultValue": {
-						"value": "Hero image description",
-						"language": "en-US"
-					}
-				},
-				"sourceUri": {
-					"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-				}
-			},
-			"barcode": {
-				"type": "QR_CODE",
-				"value": "QR code"
-			},
-			"locations": [
-				{
-					"latitude": 37.424015499999996,
-					"longitude": -122.09259560000001
-				}
-			],
-			"boardingAndSeatingInfo": {
-				"boardingGroup": "B",
-				"seatNumber": "42"
-			},
-			"reservationInfo": {
-				"confirmationCode": "Confirmation code"
-			},
-			"state": "ACTIVE",
-			"linksModuleData": {
-				"uris": [
-					{
-						"id": "LINK_MODULE_URI_ID",
-						"uri": "http://maps.google.com/",
-						"description": "Link module URI description"
-					},
-					{
-						"id": "LINK_MODULE_TEL_ID",
-						"uri": "tel:6505555555",
-						"description": "Link module tel description"
-					}
-				]
-			},
-			"imageModulesData": [
-				{
-					"id": "IMAGE_MODULE_ID",
-					"mainImage": {
-						"contentDescription": {
-							"defaultValue": {
-								"value": "Image module description",
-								"language": "en-US"
-							}
-						},
-						"sourceUri": {
-							"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-						}
-					}
-				}
-			],
-			"textModulesData": [
-				{
-					"body": "Text module body",
-					"header": "Text module header",
-					"id": "TEXT_MODULE_ID"
-				}
-			],
-			"id": "%s.%s"
+		flightObject := new(walletobjects.FlightObject)
+		flightObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+		flightObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+		flightObject.State = "ACTIVE"
+		flightObject.PassengerName = "Passenger name"
+		flightObject.ReservationInfo = &walletobjects.ReservationInfo{
+			ConfirmationCode: "Confirmation code",
 		}
-		`, issuerId, classSuffix, issuerId, objectSuffix)
+
+		flightJson, _ := json.Marshal(flightObject)
+		batchObject := fmt.Sprintf("%s", flightJson)
 
 		data += "--batch_createobjectbatch\n"
 		data += "Content-Type: application/json\n\n"
@@ -497,8 +320,7 @@ func (d *demoFlight) batchCreateObjects(issuerId, classSuffix string) {
 	}
 	data += "--batch_createobjectbatch--"
 
-	// batchUrl = 'https://walletobjects.googleapis.com/batch';
-	res, err := d.httpClient.Post(batchUrl, "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
+	res, err := d.credentials.Client(oauth2.NoContext).Post("https://walletobjects.googleapis.com/batch", "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
 
 	if err != nil {
 		fmt.Println(err)
@@ -511,11 +333,6 @@ func (d *demoFlight) batchCreateObjects(issuerId, classSuffix string) {
 // [END batch]
 
 func main() {
-	if len(os.Args) == 0 {
-		fmt.Println("Usage: go run demo_flight.go <issuer-id>")
-		os.Exit(1)
-	}
-
 	issuerId := os.Getenv("WALLET_ISSUER_ID")
 	classSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 	objectSuffix := fmt.Sprintf("%s-%s", strings.ReplaceAll(uuid.New().String(), "-", "_"), classSuffix)
@@ -527,6 +344,6 @@ func main() {
 	d.createObject(issuerId, classSuffix, objectSuffix)
 	d.expireObject(issuerId, objectSuffix)
 	d.createJwtNewObjects(issuerId, classSuffix, objectSuffix)
-	d.createJwtExistingObjects(issuerId)
+	d.createJwtExistingObjects(issuerId, classSuffix, objectSuffix)
 	d.batchCreateObjects(issuerId, classSuffix)
 }
diff --git a/go/demo_generic.go b/go/demo_generic.go
index 1e69804..5dcfeaf 100644
--- a/go/demo_generic.go
+++ b/go/demo_generic.go
@@ -20,6 +20,7 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"github.com/golang-jwt/jwt"
@@ -27,35 +28,34 @@ import (
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	oauthJwt "golang.org/x/oauth2/jwt"
+	"google.golang.org/api/option"
+	"google.golang.org/api/walletobjects/v1"
 	"io"
-	"net/http"
+	"log"
 	"os"
 	"strings"
 )
 
 // [END imports]
-
-const (
-	batchUrl  = "https://walletobjects.googleapis.com/batch"
-	classUrl  = "https://walletobjects.googleapis.com/walletobjects/v1/genericClass"
-	objectUrl = "https://walletobjects.googleapis.com/walletobjects/v1/genericObject"
-)
-
 // [END setup]
 
 type demoGeneric struct {
-	credentials                   *oauthJwt.Config
-	httpClient                    *http.Client
-	batchUrl, classUrl, objectUrl string
+	credentials *oauthJwt.Config
+	service     *walletobjects.Service
 }
 
 // [START auth]
 // Create authenticated HTTP client using a service account file.
 func (d *demoGeneric) auth() {
-	b, _ := os.ReadFile(os.Getenv("GOOGLE_APPLICATION_CREDENTIALS"))
-	credentials, _ := google.JWTConfigFromJSON(b, "https://www.googleapis.com/auth/wallet_object.issuer")
+	credentialsFile := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
+	b, _ := os.ReadFile(credentialsFile)
+	credentials, err := google.JWTConfigFromJSON(b, walletobjects.WalletObjectIssuerScope)
+	if err != nil {
+		fmt.Println(err)
+		log.Fatalf("Unable to load credentials: %v", err)
+	}
 	d.credentials = credentials
-	d.httpClient = d.credentials.Client(oauth2.NoContext)
+	d.service, _ = walletobjects.NewService(context.Background(), option.WithCredentialsFile(credentialsFile))
 }
 
 // [END auth]
@@ -63,19 +63,13 @@ func (d *demoGeneric) auth() {
 // [START createClass]
 // Create a class.
 func (d *demoGeneric) createClass(issuerId, classSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"id": "%s.%s"
-	}
-	`, issuerId, classSuffix)
-
-	res, err := d.httpClient.Post(classUrl, "application/json", bytes.NewBuffer([]byte(newClass)))
-
+	genericClass := new(walletobjects.GenericClass)
+	genericClass.Id = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	res, err := d.service.Genericclass.Insert(genericClass).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert class: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Class insert response:\n%s\n", b)
+		fmt.Printf("Class insert id:\n%v\n", res.Id)
 	}
 }
 
@@ -84,97 +78,68 @@ func (d *demoGeneric) createClass(issuerId, classSuffix string) {
 // [START createObject]
 // Create an object.
 func (d *demoGeneric) createObject(issuerId, classSuffix, objectSuffix string) {
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"cardTitle": {
-			"defaultValue": {
-				"value": "Generic card title",
-				"language": "en-US"
-			}
-		},
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"header": {
-			"defaultValue": {
-				"value": "Generic header",
-				"language": "en-US"
-			}
-		},
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"logo": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Generic card logo",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://storage.googleapis.com/wallet-lab-tools-codelab-artifacts-public/pass_google_logo.jpg"
-			}
-		},
-		"hexBackgroundColor": "#4285f4",
-		"id": "%s.%s"
+	genericObject := new(walletobjects.GenericObject)
+	genericObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	genericObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	genericObject.State = "ACTIVE"
+	genericObject.Barcode = &walletobjects.Barcode{
+		Type:  "QR_CODE",
+		Value: "QR code",
+	}
+	genericObject.CardTitle = &walletobjects.LocalizedString{
+		DefaultValue: &walletobjects.TranslatedString{
+			Language: "en-us",
+			Value:    "Card title",
+		},
+	}
+	genericObject.Header = &walletobjects.LocalizedString{
+		DefaultValue: &walletobjects.TranslatedString{
+			Language: "en-us",
+			Value:    "Header",
+		},
+	}
+	genericObject.HeroImage = &walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
+			Uri: "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg",
+		},
+	}
+	genericObject.LinksModuleData = &walletobjects.LinksModuleData{
+		Uris: []*walletobjects.Uri{
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_URI_ID",
+				Uri:         "http://maps.google.com/",
+				Description: "Link module URI description",
+			},
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_TEL_ID",
+				Uri:         "tel:6505555555",
+				Description: "Link module tel description",
+			},
+		},
+	}
+	genericObject.ImageModulesData = []*walletobjects.ImageModuleData{
+		&walletobjects.ImageModuleData{
+			Id: "IMAGE_MODULE_ID",
+			MainImage: &walletobjects.Image{
+				SourceUri: &walletobjects.ImageUri{
+					Uri: "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg",
+				},
+			},
+		},
+	}
+	genericObject.TextModulesData = []*walletobjects.TextModuleData{
+		&walletobjects.TextModuleData{
+			Body:   "Text module body",
+			Header: "Text module header",
+			Id:     "TEXT_MODULE_ID",
+		},
 	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	res, err := d.httpClient.Post(objectUrl, "application/json", bytes.NewBuffer([]byte(newObject)))
 
+	res, err := d.service.Genericobject.Insert(genericObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object insert response:\n%s\n", b)
+		fmt.Printf("Object insert id:\n%s\n", res.Id)
 	}
 }
 
@@ -186,16 +151,14 @@ func (d *demoGeneric) createObject(issuerId, classSuffix, objectSuffix string) {
 // Sets the object's state to Expired. If the valid time interval is
 // already set, the pass will expire automatically up to 24 hours after.
 func (d *demoGeneric) expireObject(issuerId, objectSuffix string) {
-	patchBody := `{"state": "EXPIRED"}`
-	url := fmt.Sprintf("%s/%s.%s", objectUrl, issuerId, objectSuffix)
-	req, _ := http.NewRequest(http.MethodPatch, url, bytes.NewBuffer([]byte(patchBody)))
-	res, err := d.httpClient.Do(req)
-
+	genericObject := &walletobjects.GenericObject{
+		State: "EXPIRED",
+	}
+	res, err := d.service.Genericobject.Patch(fmt.Sprintf("%s.%s", issuerId, objectSuffix), genericObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to patch object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object expiration response:\n%s\n", b)
+		fmt.Printf("Object expiration id:\n%s\n", res.Id)
 	}
 }
 
@@ -209,104 +172,34 @@ func (d *demoGeneric) expireObject(issuerId, objectSuffix string) {
 // created. This allows you to create multiple pass classes and objects in
 // one API call when the user saves the pass to their wallet.
 func (d *demoGeneric) createJwtNewObjects(issuerId, classSuffix, objectSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"id": "%s.%s"
+	genericObject := new(walletobjects.GenericObject)
+	genericObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	genericObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	genericObject.State = "ACTIVE"
+	genericObject.Barcode = &walletobjects.Barcode{
+		Type:  "QR_CODE",
+		Value: "QR code",
 	}
-	`, issuerId, classSuffix)
-
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"cardTitle": {
-			"defaultValue": {
-				"value": "Generic card title",
-				"language": "en-US"
-			}
+	genericObject.CardTitle = &walletobjects.LocalizedString{
+		DefaultValue: &walletobjects.TranslatedString{
+			Language: "en-us",
+			Value:    "Card title",
+		},
+	}
+	genericObject.Header = &walletobjects.LocalizedString{
+		DefaultValue: &walletobjects.TranslatedString{
+			Language: "en-us",
+			Value:    "Header",
 		},
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"header": {
-			"defaultValue": {
-				"value": "Generic header",
-				"language": "en-US"
-			}
-		},
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"logo": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Generic card logo",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://storage.googleapis.com/wallet-lab-tools-codelab-artifacts-public/pass_google_logo.jpg"
-			}
-		},
-		"hexBackgroundColor": "#4285f4",
-		"id": "%s.%s"
 	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
 
-	var payload map[string]interface{}
+	genericJson, _ := json.Marshal(genericObject)
+	var payload map[string]any
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
-		"genericClasses": [%s],
 		"genericObjects": [%s]
 	}
-	`, newClass, newObject)), &payload)
-
+	`, genericJson)), &payload)
 	claims := jwt.MapClaims{
 		"iss":     d.credentials.Email,
 		"aud":     "google",
@@ -332,7 +225,7 @@ func (d *demoGeneric) createJwtNewObjects(issuerId, classSuffix, objectSuffix st
 // their wallet, the pass objects defined in the JWT are added to the
 // user's Google Wallet app. This allows the user to save multiple pass
 // objects in one API call.
-func (d *demoGeneric) createJwtExistingObjects(issuerId string) {
+func (d *demoGeneric) createJwtExistingObjects(issuerId string, classSuffix string, objectSuffix string) {
 	var payload map[string]interface{}
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
@@ -398,89 +291,29 @@ func (d *demoGeneric) batchCreateObjects(issuerId, classSuffix string) {
 	for i := 0; i < 3; i++ {
 		objectSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 
-		batchObject := fmt.Sprintf(`
-		{
-			"classId": "%s.%s",
-			"cardTitle": {
-				"defaultValue": {
-					"value": "Generic card title",
-					"language": "en-US"
-				}
-			},
-			"heroImage": {
-				"contentDescription": {
-					"defaultValue": {
-						"value": "Hero image description",
-						"language": "en-US"
-					}
-				},
-				"sourceUri": {
-					"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-				}
-			},
-			"barcode": {
-				"type": "QR_CODE",
-				"value": "QR code"
-			},
-			"header": {
-				"defaultValue": {
-					"value": "Generic header",
-					"language": "en-US"
-				}
-			},
-			"state": "ACTIVE",
-			"linksModuleData": {
-				"uris": [
-					{
-						"id": "LINK_MODULE_URI_ID",
-						"uri": "http://maps.google.com/",
-						"description": "Link module URI description"
-					},
-					{
-						"id": "LINK_MODULE_TEL_ID",
-						"uri": "tel:6505555555",
-						"description": "Link module tel description"
-					}
-				]
-			},
-			"imageModulesData": [
-				{
-					"id": "IMAGE_MODULE_ID",
-					"mainImage": {
-						"contentDescription": {
-							"defaultValue": {
-								"value": "Image module description",
-								"language": "en-US"
-							}
-						},
-						"sourceUri": {
-							"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-						}
-					}
-				}
-			],
-			"textModulesData": [
-				{
-					"body": "Text module body",
-					"header": "Text module header",
-					"id": "TEXT_MODULE_ID"
-				}
-			],
-			"logo": {
-				"contentDescription": {
-					"defaultValue": {
-						"value": "Generic card logo",
-						"language": "en-US"
-					}
-				},
-				"sourceUri": {
-					"uri": "https://storage.googleapis.com/wallet-lab-tools-codelab-artifacts-public/pass_google_logo.jpg"
-				}
-			},
-			"hexBackgroundColor": "#4285f4",
-			"id": "%s.%s"
+		genericObject := new(walletobjects.GenericObject)
+		genericObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+		genericObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+		genericObject.State = "ACTIVE"
+		genericObject.Barcode = &walletobjects.Barcode{
+			Type:  "QR_CODE",
+			Value: "QR code",
 		}
-		`, issuerId, classSuffix, issuerId, objectSuffix)
+		genericObject.CardTitle = &walletobjects.LocalizedString{
+			DefaultValue: &walletobjects.TranslatedString{
+				Language: "en-us",
+				Value:    "Card title",
+			},
+		}
+		genericObject.Header = &walletobjects.LocalizedString{
+			DefaultValue: &walletobjects.TranslatedString{
+				Language: "en-us",
+				Value:    "Header",
+			},
+		}
+
+		genericJson, _ := json.Marshal(genericObject)
+		batchObject := fmt.Sprintf("%s", genericJson)
 
 		data += "--batch_createobjectbatch\n"
 		data += "Content-Type: application/json\n\n"
@@ -489,8 +322,7 @@ func (d *demoGeneric) batchCreateObjects(issuerId, classSuffix string) {
 	}
 	data += "--batch_createobjectbatch--"
 
-	// batchUrl = 'https://walletobjects.googleapis.com/batch';
-	res, err := d.httpClient.Post(batchUrl, "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
+	res, err := d.credentials.Client(oauth2.NoContext).Post("https://walletobjects.googleapis.com/batch", "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
 
 	if err != nil {
 		fmt.Println(err)
@@ -503,11 +335,6 @@ func (d *demoGeneric) batchCreateObjects(issuerId, classSuffix string) {
 // [END batch]
 
 func main() {
-	if len(os.Args) == 0 {
-		fmt.Println("Usage: go run demo_generic.go <issuer-id>")
-		os.Exit(1)
-	}
-
 	issuerId := os.Getenv("WALLET_ISSUER_ID")
 	classSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 	objectSuffix := fmt.Sprintf("%s-%s", strings.ReplaceAll(uuid.New().String(), "-", "_"), classSuffix)
@@ -519,6 +346,6 @@ func main() {
 	d.createObject(issuerId, classSuffix, objectSuffix)
 	d.expireObject(issuerId, objectSuffix)
 	d.createJwtNewObjects(issuerId, classSuffix, objectSuffix)
-	d.createJwtExistingObjects(issuerId)
+	d.createJwtExistingObjects(issuerId, classSuffix, objectSuffix)
 	d.batchCreateObjects(issuerId, classSuffix)
 }
diff --git a/go/demo_giftcard.go b/go/demo_giftcard.go
index 914a20b..1ad8c82 100644
--- a/go/demo_giftcard.go
+++ b/go/demo_giftcard.go
@@ -20,6 +20,7 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"github.com/golang-jwt/jwt"
@@ -27,35 +28,34 @@ import (
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	oauthJwt "golang.org/x/oauth2/jwt"
+	"google.golang.org/api/option"
+	"google.golang.org/api/walletobjects/v1"
 	"io"
-	"net/http"
+	"log"
 	"os"
 	"strings"
 )
 
 // [END imports]
-
-const (
-	batchUrl  = "https://walletobjects.googleapis.com/batch"
-	classUrl  = "https://walletobjects.googleapis.com/walletobjects/v1/giftCardClass"
-	objectUrl = "https://walletobjects.googleapis.com/walletobjects/v1/giftCardObject"
-)
-
 // [END setup]
 
 type demoGiftcard struct {
-	credentials                   *oauthJwt.Config
-	httpClient                    *http.Client
-	batchUrl, classUrl, objectUrl string
+	credentials *oauthJwt.Config
+	service     *walletobjects.Service
 }
 
 // [START auth]
 // Create authenticated HTTP client using a service account file.
 func (d *demoGiftcard) auth() {
-	b, _ := os.ReadFile(os.Getenv("GOOGLE_APPLICATION_CREDENTIALS"))
-	credentials, _ := google.JWTConfigFromJSON(b, "https://www.googleapis.com/auth/wallet_object.issuer")
+	credentialsFile := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
+	b, _ := os.ReadFile(credentialsFile)
+	credentials, err := google.JWTConfigFromJSON(b, walletobjects.WalletObjectIssuerScope)
+	if err != nil {
+		fmt.Println(err)
+		log.Fatalf("Unable to load credentials: %v", err)
+	}
 	d.credentials = credentials
-	d.httpClient = d.credentials.Client(oauth2.NoContext)
+	d.service, _ = walletobjects.NewService(context.Background(), option.WithCredentialsFile(credentialsFile))
 }
 
 // [END auth]
@@ -63,21 +63,15 @@ func (d *demoGiftcard) auth() {
 // [START createClass]
 // Create a class.
 func (d *demoGiftcard) createClass(issuerId, classSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"issuerName": "Issuer name",
-		"id": "%s.%s",
-		"reviewStatus": "UNDER_REVIEW"
-	}
-	`, issuerId, classSuffix)
-
-	res, err := d.httpClient.Post(classUrl, "application/json", bytes.NewBuffer([]byte(newClass)))
-
+	giftcardClass := new(walletobjects.GiftCardClass)
+	giftcardClass.Id = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	giftcardClass.IssuerName = "Issuer name"
+	giftcardClass.ReviewStatus = "UNDER_REVIEW"
+	res, err := d.service.Giftcardclass.Insert(giftcardClass).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert class: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Class insert response:\n%s\n", b)
+		fmt.Printf("Class insert id:\n%v\n", res.Id)
 	}
 }
 
@@ -86,88 +80,71 @@ func (d *demoGiftcard) createClass(issuerId, classSuffix string) {
 // [START createObject]
 // Create an object.
 func (d *demoGiftcard) createObject(issuerId, classSuffix, objectSuffix string) {
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"pin": "1234",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"balanceUpdateTime": {
-			"date": "2020-04-12T16:20:50.52-04:00"
-		},
-		"state": "ACTIVE",
-		"cardNumber": "Card number",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"balance": {
-			"micros": 20000000,
-			"currencyCode": "USD"
-		},
-		"id": "%s.%s"
+	giftcardObject := new(walletobjects.GiftCardObject)
+	giftcardObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	giftcardObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	giftcardObject.State = "ACTIVE"
+	giftcardObject.CardNumber = "Card number"
+	giftcardObject.Pin = "1234"
+	giftcardObject.Balance = &walletobjects.Money{
+		Micros:       20000000,
+		CurrencyCode: "USD",
+	}
+	giftcardObject.BalanceUpdateTime = &walletobjects.DateTime{
+		Date: "2023-12-12T23:20:50.52Z",
+	}
+	giftcardObject.HeroImage = &walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
+			Uri: "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg",
+		},
+	}
+	giftcardObject.Barcode = &walletobjects.Barcode{
+		Type:  "QR_CODE",
+		Value: "QR code",
+	}
+	giftcardObject.Locations = []*walletobjects.LatLongPoint{
+		&walletobjects.LatLongPoint{
+			Latitude:  37.424015499999996,
+			Longitude: -122.09259560000001,
+		},
+	}
+	giftcardObject.LinksModuleData = &walletobjects.LinksModuleData{
+		Uris: []*walletobjects.Uri{
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_URI_ID",
+				Uri:         "http://maps.google.com/",
+				Description: "Link module URI description",
+			},
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_TEL_ID",
+				Uri:         "tel:6505555555",
+				Description: "Link module tel description",
+			},
+		},
+	}
+	giftcardObject.ImageModulesData = []*walletobjects.ImageModuleData{
+		&walletobjects.ImageModuleData{
+			Id: "IMAGE_MODULE_ID",
+			MainImage: &walletobjects.Image{
+				SourceUri: &walletobjects.ImageUri{
+					Uri: "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg",
+				},
+			},
+		},
+	}
+	giftcardObject.TextModulesData = []*walletobjects.TextModuleData{
+		&walletobjects.TextModuleData{
+			Body:   "Text module body",
+			Header: "Text module header",
+			Id:     "TEXT_MODULE_ID",
+		},
 	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	res, err := d.httpClient.Post(objectUrl, "application/json", bytes.NewBuffer([]byte(newObject)))
 
+	res, err := d.service.Giftcardobject.Insert(giftcardObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object insert response:\n%s\n", b)
+		fmt.Printf("Object insert id:\n%s\n", res.Id)
 	}
 }
 
@@ -179,16 +156,14 @@ func (d *demoGiftcard) createObject(issuerId, classSuffix, objectSuffix string)
 // Sets the object's state to Expired. If the valid time interval is
 // already set, the pass will expire automatically up to 24 hours after.
 func (d *demoGiftcard) expireObject(issuerId, objectSuffix string) {
-	patchBody := `{"state": "EXPIRED"}`
-	url := fmt.Sprintf("%s/%s.%s", objectUrl, issuerId, objectSuffix)
-	req, _ := http.NewRequest(http.MethodPatch, url, bytes.NewBuffer([]byte(patchBody)))
-	res, err := d.httpClient.Do(req)
-
+	giftcardObject := &walletobjects.GiftCardObject{
+		State: "EXPIRED",
+	}
+	res, err := d.service.Giftcardobject.Patch(fmt.Sprintf("%s.%s", issuerId, objectSuffix), giftcardObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to patch object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object expiration response:\n%s\n", b)
+		fmt.Printf("Object expiration id:\n%s\n", res.Id)
 	}
 }
 
@@ -202,97 +177,19 @@ func (d *demoGiftcard) expireObject(issuerId, objectSuffix string) {
 // created. This allows you to create multiple pass classes and objects in
 // one API call when the user saves the pass to their wallet.
 func (d *demoGiftcard) createJwtNewObjects(issuerId, classSuffix, objectSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"issuerName": "Issuer name",
-		"id": "%s.%s",
-		"reviewStatus": "UNDER_REVIEW"
-	}
-	`, issuerId, classSuffix)
+	giftcardObject := new(walletobjects.GiftCardObject)
+	giftcardObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	giftcardObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	giftcardObject.State = "ACTIVE"
+	giftcardObject.CardNumber = "Card number"
 
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"pin": "1234",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"balanceUpdateTime": {
-			"date": "2020-04-12T16:20:50.52-04:00"
-		},
-		"state": "ACTIVE",
-		"cardNumber": "Card number",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"balance": {
-			"micros": 20000000,
-			"currencyCode": "USD"
-		},
-		"id": "%s.%s"
-	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	var payload map[string]interface{}
+	giftcardJson, _ := json.Marshal(giftcardObject)
+	var payload map[string]any
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
-		"genericClasses": [%s],
-		"genericObjects": [%s]
+		"giftcardObjects": [%s]
 	}
-	`, newClass, newObject)), &payload)
-
+	`, giftcardJson)), &payload)
 	claims := jwt.MapClaims{
 		"iss":     d.credentials.Email,
 		"aud":     "google",
@@ -318,7 +215,7 @@ func (d *demoGiftcard) createJwtNewObjects(issuerId, classSuffix, objectSuffix s
 // their wallet, the pass objects defined in the JWT are added to the
 // user's Google Wallet app. This allows the user to save multiple pass
 // objects in one API call.
-func (d *demoGiftcard) createJwtExistingObjects(issuerId string) {
+func (d *demoGiftcard) createJwtExistingObjects(issuerId string, classSuffix string, objectSuffix string) {
 	var payload map[string]interface{}
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
@@ -347,7 +244,7 @@ func (d *demoGiftcard) createJwtExistingObjects(issuerId string) {
 			"classId": "%s.LOYALTY_CLASS_SUFFIX"
 		}],
 
-		"offerObjects": [{
+		"giftcardObjects": [{
 			"id": "%s.OFFER_OBJECT_SUFFIX",
 			"classId": "%s.OFFER_CLASS_SUFFIX"
 		}],
@@ -384,80 +281,14 @@ func (d *demoGiftcard) batchCreateObjects(issuerId, classSuffix string) {
 	for i := 0; i < 3; i++ {
 		objectSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 
-		batchObject := fmt.Sprintf(`
-		{
-			"classId": "%s.%s",
-			"pin": "1234",
-			"heroImage": {
-				"contentDescription": {
-					"defaultValue": {
-						"value": "Hero image description",
-						"language": "en-US"
-					}
-				},
-				"sourceUri": {
-					"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-				}
-			},
-			"barcode": {
-				"type": "QR_CODE",
-				"value": "QR code"
-			},
-			"locations": [
-				{
-					"latitude": 37.424015499999996,
-					"longitude": -122.09259560000001
-				}
-			],
-			"balanceUpdateTime": {
-				"date": "2020-04-12T16:20:50.52-04:00"
-			},
-			"state": "ACTIVE",
-			"cardNumber": "Card number",
-			"linksModuleData": {
-				"uris": [
-					{
-						"id": "LINK_MODULE_URI_ID",
-						"uri": "http://maps.google.com/",
-						"description": "Link module URI description"
-					},
-					{
-						"id": "LINK_MODULE_TEL_ID",
-						"uri": "tel:6505555555",
-						"description": "Link module tel description"
-					}
-				]
-			},
-			"imageModulesData": [
-				{
-					"id": "IMAGE_MODULE_ID",
-					"mainImage": {
-						"contentDescription": {
-							"defaultValue": {
-								"value": "Image module description",
-								"language": "en-US"
-							}
-						},
-						"sourceUri": {
-							"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-						}
-					}
-				}
-			],
-			"textModulesData": [
-				{
-					"body": "Text module body",
-					"header": "Text module header",
-					"id": "TEXT_MODULE_ID"
-				}
-			],
-			"balance": {
-				"micros": 20000000,
-				"currencyCode": "USD"
-			},
-			"id": "%s.%s"
-		}
-		`, issuerId, classSuffix, issuerId, objectSuffix)
+		giftcardObject := new(walletobjects.GiftCardObject)
+		giftcardObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+		giftcardObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+		giftcardObject.State = "ACTIVE"
+		giftcardObject.CardNumber = "Card number"
+
+		giftcardJson, _ := json.Marshal(giftcardObject)
+		batchObject := fmt.Sprintf("%s", giftcardJson)
 
 		data += "--batch_createobjectbatch\n"
 		data += "Content-Type: application/json\n\n"
@@ -466,8 +297,7 @@ func (d *demoGiftcard) batchCreateObjects(issuerId, classSuffix string) {
 	}
 	data += "--batch_createobjectbatch--"
 
-	// batchUrl = 'https://walletobjects.googleapis.com/batch';
-	res, err := d.httpClient.Post(batchUrl, "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
+	res, err := d.credentials.Client(oauth2.NoContext).Post("https://walletobjects.googleapis.com/batch", "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
 
 	if err != nil {
 		fmt.Println(err)
@@ -480,11 +310,6 @@ func (d *demoGiftcard) batchCreateObjects(issuerId, classSuffix string) {
 // [END batch]
 
 func main() {
-	if len(os.Args) == 0 {
-		fmt.Println("Usage: go run demo_giftcard.go <issuer-id>")
-		os.Exit(1)
-	}
-
 	issuerId := os.Getenv("WALLET_ISSUER_ID")
 	classSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 	objectSuffix := fmt.Sprintf("%s-%s", strings.ReplaceAll(uuid.New().String(), "-", "_"), classSuffix)
@@ -496,6 +321,6 @@ func main() {
 	d.createObject(issuerId, classSuffix, objectSuffix)
 	d.expireObject(issuerId, objectSuffix)
 	d.createJwtNewObjects(issuerId, classSuffix, objectSuffix)
-	d.createJwtExistingObjects(issuerId)
+	d.createJwtExistingObjects(issuerId, classSuffix, objectSuffix)
 	d.batchCreateObjects(issuerId, classSuffix)
 }
diff --git a/go/demo_loyalty.go b/go/demo_loyalty.go
index 14e7d3a..c1f6310 100644
--- a/go/demo_loyalty.go
+++ b/go/demo_loyalty.go
@@ -20,35 +20,28 @@ package main
 
 import (
 	"bytes"
-        "context"
+	"context"
 	"encoding/json"
 	"fmt"
-	"log"
-
 	"github.com/golang-jwt/jwt"
 	"github.com/google/uuid"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	oauthJwt "golang.org/x/oauth2/jwt"
-        "google.golang.org/api/option"
-        "google.golang.org/api/walletobjects/v1"
+	"google.golang.org/api/option"
+	"google.golang.org/api/walletobjects/v1"
 	"io"
+	"log"
 	"os"
 	"strings"
 )
 
 // [END imports]
-
-const (
-	batchUrl  = "https://walletobjects.googleapis.com/batch"
-)
-
 // [END setup]
 
 type demoLoyalty struct {
 	credentials *oauthJwt.Config
-	service *walletobjects.Service
-	batchUrl string
+	service     *walletobjects.Service
 }
 
 // [START auth]
@@ -58,7 +51,8 @@ func (d *demoLoyalty) auth() {
 	b, _ := os.ReadFile(credentialsFile)
 	credentials, err := google.JWTConfigFromJSON(b, walletobjects.WalletObjectIssuerScope)
 	if err != nil {
-		log.Fatalf("Unable to create credentials: %v", err)
+		fmt.Println(err)
+		log.Fatalf("Unable to load credentials: %v", err)
 	}
 	d.credentials = credentials
 	d.service, _ = walletobjects.NewService(context.Background(), option.WithCredentialsFile(credentialsFile))
@@ -69,8 +63,8 @@ func (d *demoLoyalty) auth() {
 // [START createClass]
 // Create a class.
 func (d *demoLoyalty) createClass(issuerId, classSuffix string) {
-	logo := walletobjects.Image {
-		SourceUri: &walletobjects.ImageUri {
+	logo := walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
 			Uri: "http://farm8.staticflickr.com/7340/11177041185_a61a7f2139_o.jpg",
 		},
 	}
@@ -90,73 +84,66 @@ func (d *demoLoyalty) createClass(issuerId, classSuffix string) {
 
 // [END createClass]
 
-// [START setupObject]
-// Build a full loyaltyObject.
-func (d *demoLoyalty) setupObject(issuerId, classSuffix, objectSuffix string) *walletobjects.LoyaltyObject {
+// [START createObject]
+// Create an object.
+func (d *demoLoyalty) createObject(issuerId, classSuffix, objectSuffix string) {
 	loyaltyObject := new(walletobjects.LoyaltyObject)
 	loyaltyObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
 	loyaltyObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
 	loyaltyObject.AccountName = "Account name"
 	loyaltyObject.AccountId = "Account id"
 	loyaltyObject.State = "ACTIVE"
-	loyaltyObject.LoyaltyPoints = &walletobjects.LoyaltyPoints {
-		Balance: &walletobjects.LoyaltyPointsBalance { Int: 800 },
-		Label: "Points",
+	loyaltyObject.LoyaltyPoints = &walletobjects.LoyaltyPoints{
+		Balance: &walletobjects.LoyaltyPointsBalance{Int: 800},
+		Label:   "Points",
 	}
-	loyaltyObject.HeroImage = &walletobjects.Image {
-		SourceUri: &walletobjects.ImageUri {
+	loyaltyObject.HeroImage = &walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
 			Uri: "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg",
 		},
 	}
-	loyaltyObject.Barcode = &walletobjects.Barcode {
-		Type: "QR_CODE",
+	loyaltyObject.Barcode = &walletobjects.Barcode{
+		Type:  "QR_CODE",
 		Value: "QR code",
 	}
-	loyaltyObject.Locations = []*walletobjects.LatLongPoint {
-		&walletobjects.LatLongPoint {
-			Latitude: 37.424015499999996,
+	loyaltyObject.Locations = []*walletobjects.LatLongPoint{
+		&walletobjects.LatLongPoint{
+			Latitude:  37.424015499999996,
 			Longitude: -122.09259560000001,
 		},
 	}
-	loyaltyObject.LinksModuleData = &walletobjects.LinksModuleData {
-		Uris: []*walletobjects.Uri {
-			&walletobjects.Uri {
-				Id: "LINK_MODULE_URI_ID",
-				Uri: "http://maps.google.com/",
+	loyaltyObject.LinksModuleData = &walletobjects.LinksModuleData{
+		Uris: []*walletobjects.Uri{
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_URI_ID",
+				Uri:         "http://maps.google.com/",
 				Description: "Link module URI description",
 			},
-			&walletobjects.Uri {
-				Id: "LINK_MODULE_TEL_ID",
-				Uri: "tel:6505555555",
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_TEL_ID",
+				Uri:         "tel:6505555555",
 				Description: "Link module tel description",
 			},
 		},
 	}
-	loyaltyObject.ImageModulesData = []*walletobjects.ImageModuleData {
-		&walletobjects.ImageModuleData {
+	loyaltyObject.ImageModulesData = []*walletobjects.ImageModuleData{
+		&walletobjects.ImageModuleData{
 			Id: "IMAGE_MODULE_ID",
-			MainImage: &walletobjects.Image {
+			MainImage: &walletobjects.Image{
 				SourceUri: &walletobjects.ImageUri{
 					Uri: "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg",
 				},
 			},
 		},
 	}
-	loyaltyObject.TextModulesData = []*walletobjects.TextModuleData {
-		&walletobjects.TextModuleData {
-			Body: "Text module body",
+	loyaltyObject.TextModulesData = []*walletobjects.TextModuleData{
+		&walletobjects.TextModuleData{
+			Body:   "Text module body",
 			Header: "Text module header",
-			Id: "TEXT_MODULE_ID",
+			Id:     "TEXT_MODULE_ID",
 		},
 	}
-	return loyaltyObject
-}
-// [END setupObject]
 
-// [START createObject]
-// Create an object.
-func (d *demoLoyalty) createObject(issuerId, classSuffix, objectSuffix string) {
-	loyaltyObject := d.setupObject(issuerId, classSuffix, objectSuffix)
 	res, err := d.service.Loyaltyobject.Insert(loyaltyObject).Do()
 	if err != nil {
 		log.Fatalf("Unable to insert object: %v", err)
@@ -173,7 +160,7 @@ func (d *demoLoyalty) createObject(issuerId, classSuffix, objectSuffix string) {
 // Sets the object's state to Expired. If the valid time interval is
 // already set, the pass will expire automatically up to 24 hours after.
 func (d *demoLoyalty) expireObject(issuerId, objectSuffix string) {
-	loyaltyObject := &walletobjects.LoyaltyObject {
+	loyaltyObject := &walletobjects.LoyaltyObject{
 		State: "EXPIRED",
 	}
 	res, err := d.service.Loyaltyobject.Patch(fmt.Sprintf("%s.%s", issuerId, objectSuffix), loyaltyObject).Do()
@@ -195,11 +182,12 @@ func (d *demoLoyalty) expireObject(issuerId, objectSuffix string) {
 // one API call when the user saves the pass to their wallet.
 func (d *demoLoyalty) createJwtNewObjects(issuerId, classSuffix, objectSuffix string) {
 	loyaltyObject := new(walletobjects.LoyaltyObject)
-	loyaltyObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix + "_")
+	loyaltyObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix+"_")
 	loyaltyObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
 	loyaltyObject.AccountName = "Account name"
 	loyaltyObject.AccountId = "Account id"
 	loyaltyObject.State = "ACTIVE"
+
 	loyaltyJson, _ := json.Marshal(loyaltyObject)
 	var payload map[string]any
 	json.Unmarshal([]byte(fmt.Sprintf(`
@@ -233,16 +221,46 @@ func (d *demoLoyalty) createJwtNewObjects(issuerId, classSuffix, objectSuffix st
 // user's Google Wallet app. This allows the user to save multiple pass
 // objects in one API call.
 func (d *demoLoyalty) createJwtExistingObjects(issuerId string, classSuffix string, objectSuffix string) {
-	loyaltyObject := new(walletobjects.LoyaltyObject)
-	loyaltyObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
-	loyaltyObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
-	loyaltyJson, _ := json.Marshal(loyaltyObject)
-	var payload map[string]any
+	var payload map[string]interface{}
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
-		"loyaltyObjects":[%s]
+		"eventTicketObjects": [{
+			"id": "%s.EVENT_OBJECT_SUFFIX",
+			"classId": "%s.EVENT_CLASS_SUFFIX"
+		}],
+
+		"flightObjects": [{
+			"id": "%s.FLIGHT_OBJECT_SUFFIX",
+			"classId": "%s.FLIGHT_CLASS_SUFFIX"
+		}],
+
+		"genericObjects": [{
+			"id": "%s.GENERIC_OBJECT_SUFFIX",
+			"classId": "%s.GENERIC_CLASS_SUFFIX"
+		}],
+
+		"giftCardObjects": [{
+			"id": "%s.GIFT_CARD_OBJECT_SUFFIX",
+			"classId": "%s.GIFT_CARD_CLASS_SUFFIX"
+		}],
+
+		"loyaltyObjects": [{
+			"id": "%s.LOYALTY_OBJECT_SUFFIX",
+			"classId": "%s.LOYALTY_CLASS_SUFFIX"
+		}],
+
+		"offerObjects": [{
+			"id": "%s.OFFER_OBJECT_SUFFIX",
+			"classId": "%s.OFFER_CLASS_SUFFIX"
+		}],
+
+		"transitObjects": [{
+			"id": "%s.TRANSIT_OBJECT_SUFFIX",
+			"classId": "%s.TRANSIT_CLASS_SUFFIX"
+		}]
 	}
-	`, loyaltyJson )), &payload)
+	`, issuerId)), &payload)
+
 	claims := jwt.MapClaims{
 		"iss":     d.credentials.Email,
 		"aud":     "google",
@@ -255,7 +273,7 @@ func (d *demoLoyalty) createJwtExistingObjects(issuerId string, classSuffix stri
 	key, _ := jwt.ParseRSAPrivateKeyFromPEM(d.credentials.PrivateKey)
 	token, _ := jwt.NewWithClaims(jwt.SigningMethodRS256, claims).SignedString(key)
 
-	fmt.Println("Add to Google Wallet link for existing objects")
+	fmt.Println("Add to Google Wallet link")
 	fmt.Println("https://pay.google.com/gp/v/save/" + token)
 }
 
@@ -267,9 +285,15 @@ func (d *demoLoyalty) batchCreateObjects(issuerId, classSuffix string) {
 	data := ""
 	for i := 0; i < 3; i++ {
 		objectSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
-		loyaltyObject := d.setupObject(issuerId, classSuffix, objectSuffix)
+
+		loyaltyObject := new(walletobjects.LoyaltyObject)
+		loyaltyObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+		loyaltyObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+		loyaltyObject.AccountName = "Account name"
+		loyaltyObject.AccountId = "Account id"
+		loyaltyObject.State = "ACTIVE"
+
 		loyaltyJson, _ := json.Marshal(loyaltyObject)
-	
 		batchObject := fmt.Sprintf("%s", loyaltyJson)
 
 		data += "--batch_createobjectbatch\n"
@@ -279,7 +303,7 @@ func (d *demoLoyalty) batchCreateObjects(issuerId, classSuffix string) {
 	}
 	data += "--batch_createobjectbatch--"
 
-	res, err := d.credentials.Client(oauth2.NoContext).Post(batchUrl, "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
+	res, err := d.credentials.Client(oauth2.NoContext).Post("https://walletobjects.googleapis.com/batch", "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
 
 	if err != nil {
 		fmt.Println(err)
@@ -292,11 +316,6 @@ func (d *demoLoyalty) batchCreateObjects(issuerId, classSuffix string) {
 // [END batch]
 
 func main() {
-	if len(os.Args) == 0 {
-		fmt.Println("Usage: go run demo_loyalty.go <issuer-id>")
-		os.Exit(1)
-	}
-
 	issuerId := os.Getenv("WALLET_ISSUER_ID")
 	classSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 	objectSuffix := fmt.Sprintf("%s-%s", strings.ReplaceAll(uuid.New().String(), "-", "_"), classSuffix)
diff --git a/go/demo_offer.go b/go/demo_offer.go
index dc4bf05..29355bc 100644
--- a/go/demo_offer.go
+++ b/go/demo_offer.go
@@ -20,6 +20,7 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"github.com/golang-jwt/jwt"
@@ -27,35 +28,34 @@ import (
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	oauthJwt "golang.org/x/oauth2/jwt"
+	"google.golang.org/api/option"
+	"google.golang.org/api/walletobjects/v1"
 	"io"
-	"net/http"
+	"log"
 	"os"
 	"strings"
 )
 
 // [END imports]
-
-const (
-	batchUrl  = "https://walletobjects.googleapis.com/batch"
-	classUrl  = "https://walletobjects.googleapis.com/walletobjects/v1/offerClass"
-	objectUrl = "https://walletobjects.googleapis.com/walletobjects/v1/offerObject"
-)
-
 // [END setup]
 
 type demoOffer struct {
-	credentials                   *oauthJwt.Config
-	httpClient                    *http.Client
-	batchUrl, classUrl, objectUrl string
+	credentials *oauthJwt.Config
+	service     *walletobjects.Service
 }
 
 // [START auth]
 // Create authenticated HTTP client using a service account file.
 func (d *demoOffer) auth() {
-	b, _ := os.ReadFile(os.Getenv("GOOGLE_APPLICATION_CREDENTIALS"))
-	credentials, _ := google.JWTConfigFromJSON(b, "https://www.googleapis.com/auth/wallet_object.issuer")
+	credentialsFile := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
+	b, _ := os.ReadFile(credentialsFile)
+	credentials, err := google.JWTConfigFromJSON(b, walletobjects.WalletObjectIssuerScope)
+	if err != nil {
+		fmt.Println(err)
+		log.Fatalf("Unable to load credentials: %v", err)
+	}
 	d.credentials = credentials
-	d.httpClient = d.credentials.Client(oauth2.NoContext)
+	d.service, _ = walletobjects.NewService(context.Background(), option.WithCredentialsFile(credentialsFile))
 }
 
 // [END auth]
@@ -63,24 +63,18 @@ func (d *demoOffer) auth() {
 // [START createClass]
 // Create a class.
 func (d *demoOffer) createClass(issuerId, classSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"redemptionChannel": "ONLINE",
-		"reviewStatus": "UNDER_REVIEW",
-		"title": "Offer title",
-		"issuerName": "Issuer name",
-		"provider": "Provider name",
-		"id": "%s.%s"
-	}
-	`, issuerId, classSuffix)
-
-	res, err := d.httpClient.Post(classUrl, "application/json", bytes.NewBuffer([]byte(newClass)))
-
+	offerClass := new(walletobjects.OfferClass)
+	offerClass.Id = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	offerClass.RedemptionChannel = "ONLINE"
+	offerClass.ReviewStatus = "UNDER_REVIEW"
+	offerClass.Title = "Offer title"
+	offerClass.IssuerName = "Issuer name"
+	offerClass.Provider = "Provider name"
+	res, err := d.service.Offerclass.Insert(offerClass).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert class: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Class insert response:\n%s\n", b)
+		fmt.Printf("Class insert id:\n%v\n", res.Id)
 	}
 }
 
@@ -89,87 +83,70 @@ func (d *demoOffer) createClass(issuerId, classSuffix string) {
 // [START createObject]
 // Create an object.
 func (d *demoOffer) createObject(issuerId, classSuffix, objectSuffix string) {
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
+	offerObject := new(walletobjects.OfferObject)
+	offerObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	offerObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	offerObject.State = "ACTIVE"
+	offerObject.ValidTimeInterval = &walletobjects.TimeInterval{
+		Start: &walletobjects.DateTime{
+			Date: "2023-06-12T23:20:50.52Z",
 		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
+		End: &walletobjects.DateTime{
+			Date: "2023-12-12T23:20:50.52Z",
+		},
+	}
+	offerObject.HeroImage = &walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
+			Uri: "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg",
+		},
+	}
+	offerObject.Barcode = &walletobjects.Barcode{
+		Type:  "QR_CODE",
+		Value: "QR code",
+	}
+	offerObject.Locations = []*walletobjects.LatLongPoint{
+		&walletobjects.LatLongPoint{
+			Latitude:  37.424015499999996,
+			Longitude: -122.09259560000001,
+		},
+	}
+	offerObject.LinksModuleData = &walletobjects.LinksModuleData{
+		Uris: []*walletobjects.Uri{
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_URI_ID",
+				Uri:         "http://maps.google.com/",
+				Description: "Link module URI description",
+			},
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_TEL_ID",
+				Uri:         "tel:6505555555",
+				Description: "Link module tel description",
+			},
+		},
+	}
+	offerObject.ImageModulesData = []*walletobjects.ImageModuleData{
+		&walletobjects.ImageModuleData{
+			Id: "IMAGE_MODULE_ID",
+			MainImage: &walletobjects.Image{
+				SourceUri: &walletobjects.ImageUri{
+					Uri: "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg",
+				},
+			},
+		},
+	}
+	offerObject.TextModulesData = []*walletobjects.TextModuleData{
+		&walletobjects.TextModuleData{
+			Body:   "Text module body",
+			Header: "Text module header",
+			Id:     "TEXT_MODULE_ID",
 		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"validTimeInterval": {
-			"start": {
-				"date": "2023-06-12T23:20:50.52Z"
-			},
-			"end": {
-				"date": "2023-12-12T23:20:50.52Z"
-			}
-		},
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"id": "%s.%s"
 	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	res, err := d.httpClient.Post(objectUrl, "application/json", bytes.NewBuffer([]byte(newObject)))
 
+	res, err := d.service.Offerobject.Insert(offerObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object insert response:\n%s\n", b)
+		fmt.Printf("Object insert id:\n%s\n", res.Id)
 	}
 }
 
@@ -181,16 +158,14 @@ func (d *demoOffer) createObject(issuerId, classSuffix, objectSuffix string) {
 // Sets the object's state to Expired. If the valid time interval is
 // already set, the pass will expire automatically up to 24 hours after.
 func (d *demoOffer) expireObject(issuerId, objectSuffix string) {
-	patchBody := `{"state": "EXPIRED"}`
-	url := fmt.Sprintf("%s/%s.%s", objectUrl, issuerId, objectSuffix)
-	req, _ := http.NewRequest(http.MethodPatch, url, bytes.NewBuffer([]byte(patchBody)))
-	res, err := d.httpClient.Do(req)
-
+	offerObject := &walletobjects.OfferObject{
+		State: "EXPIRED",
+	}
+	res, err := d.service.Offerobject.Patch(fmt.Sprintf("%s.%s", issuerId, objectSuffix), offerObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to patch object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object expiration response:\n%s\n", b)
+		fmt.Printf("Object expiration id:\n%s\n", res.Id)
 	}
 }
 
@@ -204,99 +179,18 @@ func (d *demoOffer) expireObject(issuerId, objectSuffix string) {
 // created. This allows you to create multiple pass classes and objects in
 // one API call when the user saves the pass to their wallet.
 func (d *demoOffer) createJwtNewObjects(issuerId, classSuffix, objectSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"redemptionChannel": "ONLINE",
-		"reviewStatus": "UNDER_REVIEW",
-		"title": "Offer title",
-		"issuerName": "Issuer name",
-		"provider": "Provider name",
-		"id": "%s.%s"
-	}
-	`, issuerId, classSuffix)
+	offerObject := new(walletobjects.OfferObject)
+	offerObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	offerObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	offerObject.State = "ACTIVE"
 
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"validTimeInterval": {
-			"start": {
-				"date": "2023-06-12T23:20:50.52Z"
-			},
-			"end": {
-				"date": "2023-12-12T23:20:50.52Z"
-			}
-		},
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"id": "%s.%s"
-	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	var payload map[string]interface{}
+	offerJson, _ := json.Marshal(offerObject)
+	var payload map[string]any
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
-		"genericClasses": [%s],
-		"genericObjects": [%s]
+		"offerObjects": [%s]
 	}
-	`, newClass, newObject)), &payload)
-
+	`, offerJson)), &payload)
 	claims := jwt.MapClaims{
 		"iss":     d.credentials.Email,
 		"aud":     "google",
@@ -322,7 +216,7 @@ func (d *demoOffer) createJwtNewObjects(issuerId, classSuffix, objectSuffix stri
 // their wallet, the pass objects defined in the JWT are added to the
 // user's Google Wallet app. This allows the user to save multiple pass
 // objects in one API call.
-func (d *demoOffer) createJwtExistingObjects(issuerId string) {
+func (d *demoOffer) createJwtExistingObjects(issuerId string, classSuffix string, objectSuffix string) {
 	var payload map[string]interface{}
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
@@ -388,79 +282,13 @@ func (d *demoOffer) batchCreateObjects(issuerId, classSuffix string) {
 	for i := 0; i < 3; i++ {
 		objectSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 
-		batchObject := fmt.Sprintf(`
-		{
-			"classId": "%s.%s",
-			"heroImage": {
-				"contentDescription": {
-					"defaultValue": {
-						"value": "Hero image description",
-						"language": "en-US"
-					}
-				},
-				"sourceUri": {
-					"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-				}
-			},
-			"barcode": {
-				"type": "QR_CODE",
-				"value": "QR code"
-			},
-			"locations": [
-				{
-					"latitude": 37.424015499999996,
-					"longitude": -122.09259560000001
-				}
-			],
-			"validTimeInterval": {
-				"start": {
-					"date": "2023-06-12T23:20:50.52Z"
-				},
-				"end": {
-					"date": "2023-12-12T23:20:50.52Z"
-				}
-			},
-			"state": "ACTIVE",
-			"linksModuleData": {
-				"uris": [
-					{
-						"id": "LINK_MODULE_URI_ID",
-						"uri": "http://maps.google.com/",
-						"description": "Link module URI description"
-					},
-					{
-						"id": "LINK_MODULE_TEL_ID",
-						"uri": "tel:6505555555",
-						"description": "Link module tel description"
-					}
-				]
-			},
-			"imageModulesData": [
-				{
-					"id": "IMAGE_MODULE_ID",
-					"mainImage": {
-						"contentDescription": {
-							"defaultValue": {
-								"value": "Image module description",
-								"language": "en-US"
-							}
-						},
-						"sourceUri": {
-							"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-						}
-					}
-				}
-			],
-			"textModulesData": [
-				{
-					"body": "Text module body",
-					"header": "Text module header",
-					"id": "TEXT_MODULE_ID"
-				}
-			],
-			"id": "%s.%s"
-		}
-		`, issuerId, classSuffix, issuerId, objectSuffix)
+		offerObject := new(walletobjects.OfferObject)
+		offerObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+		offerObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+		offerObject.State = "ACTIVE"
+
+		offerJson, _ := json.Marshal(offerObject)
+		batchObject := fmt.Sprintf("%s", offerJson)
 
 		data += "--batch_createobjectbatch\n"
 		data += "Content-Type: application/json\n\n"
@@ -469,8 +297,7 @@ func (d *demoOffer) batchCreateObjects(issuerId, classSuffix string) {
 	}
 	data += "--batch_createobjectbatch--"
 
-	// batchUrl = 'https://walletobjects.googleapis.com/batch';
-	res, err := d.httpClient.Post(batchUrl, "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
+	res, err := d.credentials.Client(oauth2.NoContext).Post("https://walletobjects.googleapis.com/batch", "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
 
 	if err != nil {
 		fmt.Println(err)
@@ -483,11 +310,6 @@ func (d *demoOffer) batchCreateObjects(issuerId, classSuffix string) {
 // [END batch]
 
 func main() {
-	if len(os.Args) == 0 {
-		fmt.Println("Usage: go run demo_offer.go <issuer-id>")
-		os.Exit(1)
-	}
-
 	issuerId := os.Getenv("WALLET_ISSUER_ID")
 	classSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 	objectSuffix := fmt.Sprintf("%s-%s", strings.ReplaceAll(uuid.New().String(), "-", "_"), classSuffix)
@@ -499,6 +321,6 @@ func main() {
 	d.createObject(issuerId, classSuffix, objectSuffix)
 	d.expireObject(issuerId, objectSuffix)
 	d.createJwtNewObjects(issuerId, classSuffix, objectSuffix)
-	d.createJwtExistingObjects(issuerId)
+	d.createJwtExistingObjects(issuerId, classSuffix, objectSuffix)
 	d.batchCreateObjects(issuerId, classSuffix)
 }
diff --git a/go/demo_transit.go b/go/demo_transit.go
index 6c5a83a..0bf690a 100644
--- a/go/demo_transit.go
+++ b/go/demo_transit.go
@@ -20,6 +20,7 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"github.com/golang-jwt/jwt"
@@ -27,35 +28,34 @@ import (
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	oauthJwt "golang.org/x/oauth2/jwt"
+	"google.golang.org/api/option"
+	"google.golang.org/api/walletobjects/v1"
 	"io"
-	"net/http"
+	"log"
 	"os"
 	"strings"
 )
 
 // [END imports]
-
-const (
-	batchUrl  = "https://walletobjects.googleapis.com/batch"
-	classUrl  = "https://walletobjects.googleapis.com/walletobjects/v1/transitClass"
-	objectUrl = "https://walletobjects.googleapis.com/walletobjects/v1/transitObject"
-)
-
 // [END setup]
 
 type demoTransit struct {
-	credentials                   *oauthJwt.Config
-	httpClient                    *http.Client
-	batchUrl, classUrl, objectUrl string
+	credentials *oauthJwt.Config
+	service     *walletobjects.Service
 }
 
 // [START auth]
 // Create authenticated HTTP client using a service account file.
 func (d *demoTransit) auth() {
-	b, _ := os.ReadFile(os.Getenv("GOOGLE_APPLICATION_CREDENTIALS"))
-	credentials, _ := google.JWTConfigFromJSON(b, "https://www.googleapis.com/auth/wallet_object.issuer")
+	credentialsFile := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
+	b, _ := os.ReadFile(credentialsFile)
+	credentials, err := google.JWTConfigFromJSON(b, walletobjects.WalletObjectIssuerScope)
+	if err != nil {
+		fmt.Println(err)
+		log.Fatalf("Unable to load credentials: %v", err)
+	}
 	d.credentials = credentials
-	d.httpClient = d.credentials.Client(oauth2.NoContext)
+	d.service, _ = walletobjects.NewService(context.Background(), option.WithCredentialsFile(credentialsFile))
 }
 
 // [END auth]
@@ -63,33 +63,22 @@ func (d *demoTransit) auth() {
 // [START createClass]
 // Create a class.
 func (d *demoTransit) createClass(issuerId, classSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"logo": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Logo description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://live.staticflickr.com/65535/48690277162_cd05f03f4d_o.png"
-			}
+	logo := walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
+			Uri: "http://farm8.staticflickr.com/7340/11177041185_a61a7f2139_o.jpg",
 		},
-		"issuerName": "Issuer name",
-		"reviewStatus": "UNDER_REVIEW",
-		"id": "%s.%s",
-		"transitType": "BUS"
 	}
-	`, issuerId, classSuffix)
-
-	res, err := d.httpClient.Post(classUrl, "application/json", bytes.NewBuffer([]byte(newClass)))
-
+	transitClass := new(walletobjects.TransitClass)
+	transitClass.Id = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	transitClass.IssuerName = "Issuer name"
+	transitClass.ReviewStatus = "UNDER_REVIEW"
+	transitClass.Logo = &logo
+	transitClass.TransitType = "BUS"
+	res, err := d.service.Transitclass.Insert(transitClass).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert class: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Class insert response:\n%s\n", b)
+		fmt.Printf("Class insert id:\n%v\n", res.Id)
 	}
 }
 
@@ -98,106 +87,68 @@ func (d *demoTransit) createClass(issuerId, classSuffix string) {
 // [START createObject]
 // Create an object.
 func (d *demoTransit) createObject(issuerId, classSuffix, objectSuffix string) {
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"passengerNames": "Passenger names",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"ticketLeg": {
-			"destinationStationCode": "SFO",
-			"destinationName": {
-				"defaultValue": {
-					"value": "Destination name",
-					"language": "en-US"
-				}
-			},
-			"arrivalDateTime": "2020-04-12T20:20:50.52Z",
-			"originStationCode": "LA",
-			"originName": {
-				"defaultValue": {
-					"value": "Origin name",
-					"language": "en-US"
-				}
-			},
-			"departureDateTime": "2020-04-12T16:20:50.52Z",
-			"fareName": {
-				"defaultValue": {
-					"value": "Fare name",
-					"language": "en-US"
-				}
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"passengerType": "SINGLE_PASSENGER",
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"tripType": "ONE_WAY",
-		"id": "%s.%s"
+	transitObject := new(walletobjects.TransitObject)
+	transitObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	transitObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	transitObject.State = "ACTIVE"
+	transitObject.PassengerNames = "Passenger names"
+	transitObject.TripType = "ONE_WAY"
+	transitObject.PassengerType = "SINGLE_PASSENGER"
+	transitObject.TicketLeg = &walletobjects.TicketLeg{
+		DestinationStationCode: "SFO",
+		OriginStationCode:      "LA",
 	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	res, err := d.httpClient.Post(objectUrl, "application/json", bytes.NewBuffer([]byte(newObject)))
-
+	transitObject.HeroImage = &walletobjects.Image{
+		SourceUri: &walletobjects.ImageUri{
+			Uri: "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg",
+		},
+	}
+	transitObject.Barcode = &walletobjects.Barcode{
+		Type:  "QR_CODE",
+		Value: "QR code",
+	}
+	transitObject.Locations = []*walletobjects.LatLongPoint{
+		&walletobjects.LatLongPoint{
+			Latitude:  37.424015499999996,
+			Longitude: -122.09259560000001,
+		},
+	}
+	transitObject.LinksModuleData = &walletobjects.LinksModuleData{
+		Uris: []*walletobjects.Uri{
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_URI_ID",
+				Uri:         "http://maps.google.com/",
+				Description: "Link module URI description",
+			},
+			&walletobjects.Uri{
+				Id:          "LINK_MODULE_TEL_ID",
+				Uri:         "tel:6505555555",
+				Description: "Link module tel description",
+			},
+		},
+	}
+	transitObject.ImageModulesData = []*walletobjects.ImageModuleData{
+		&walletobjects.ImageModuleData{
+			Id: "IMAGE_MODULE_ID",
+			MainImage: &walletobjects.Image{
+				SourceUri: &walletobjects.ImageUri{
+					Uri: "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg",
+				},
+			},
+		},
+	}
+	transitObject.TextModulesData = []*walletobjects.TextModuleData{
+		&walletobjects.TextModuleData{
+			Body:   "Text module body",
+			Header: "Text module header",
+			Id:     "TEXT_MODULE_ID",
+		},
+	}
+	res, err := d.service.Transitobject.Insert(transitObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to insert object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object insert response:\n%s\n", b)
+		fmt.Printf("Object insert id:\n%s\n", res.Id)
 	}
 }
 
@@ -209,16 +160,14 @@ func (d *demoTransit) createObject(issuerId, classSuffix, objectSuffix string) {
 // Sets the object's state to Expired. If the valid time interval is
 // already set, the pass will expire automatically up to 24 hours after.
 func (d *demoTransit) expireObject(issuerId, objectSuffix string) {
-	patchBody := `{"state": "EXPIRED"}`
-	url := fmt.Sprintf("%s/%s.%s", objectUrl, issuerId, objectSuffix)
-	req, _ := http.NewRequest(http.MethodPatch, url, bytes.NewBuffer([]byte(patchBody)))
-	res, err := d.httpClient.Do(req)
-
+	transitObject := &walletobjects.TransitObject{
+		State: "EXPIRED",
+	}
+	res, err := d.service.Transitobject.Patch(fmt.Sprintf("%s.%s", issuerId, objectSuffix), transitObject).Do()
 	if err != nil {
-		fmt.Println(err)
+		log.Fatalf("Unable to patch object: %v", err)
 	} else {
-		b, _ := io.ReadAll(res.Body)
-		fmt.Printf("Object expiration response:\n%s\n", b)
+		fmt.Printf("Object expiration id:\n%s\n", res.Id)
 	}
 }
 
@@ -232,127 +181,25 @@ func (d *demoTransit) expireObject(issuerId, objectSuffix string) {
 // created. This allows you to create multiple pass classes and objects in
 // one API call when the user saves the pass to their wallet.
 func (d *demoTransit) createJwtNewObjects(issuerId, classSuffix, objectSuffix string) {
-	newClass := fmt.Sprintf(`
-	{
-		"logo": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Logo description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://live.staticflickr.com/65535/48690277162_cd05f03f4d_o.png"
-			}
-		},
-		"issuerName": "Issuer name",
-		"reviewStatus": "UNDER_REVIEW",
-		"id": "%s.%s",
-		"transitType": "BUS"
+	transitObject := new(walletobjects.TransitObject)
+	transitObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+	transitObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+	transitObject.State = "ACTIVE"
+	transitObject.PassengerNames = "Passenger names"
+	transitObject.TripType = "ONE_WAY"
+	transitObject.PassengerType = "SINGLE_PASSENGER"
+	transitObject.TicketLeg = &walletobjects.TicketLeg{
+		DestinationStationCode: "SFO",
+		OriginStationCode:      "LA",
 	}
-	`, issuerId, classSuffix)
 
-	newObject := fmt.Sprintf(`
-	{
-		"classId": "%s.%s",
-		"passengerNames": "Passenger names",
-		"heroImage": {
-			"contentDescription": {
-				"defaultValue": {
-					"value": "Hero image description",
-					"language": "en-US"
-				}
-			},
-			"sourceUri": {
-				"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-			}
-		},
-		"ticketLeg": {
-			"destinationStationCode": "SFO",
-			"destinationName": {
-				"defaultValue": {
-					"value": "Destination name",
-					"language": "en-US"
-				}
-			},
-			"arrivalDateTime": "2020-04-12T20:20:50.52Z",
-			"originStationCode": "LA",
-			"originName": {
-				"defaultValue": {
-					"value": "Origin name",
-					"language": "en-US"
-				}
-			},
-			"departureDateTime": "2020-04-12T16:20:50.52Z",
-			"fareName": {
-				"defaultValue": {
-					"value": "Fare name",
-					"language": "en-US"
-				}
-			}
-		},
-		"barcode": {
-			"type": "QR_CODE",
-			"value": "QR code"
-		},
-		"locations": [
-			{
-				"latitude": 37.424015499999996,
-				"longitude": -122.09259560000001
-			}
-		],
-		"passengerType": "SINGLE_PASSENGER",
-		"state": "ACTIVE",
-		"linksModuleData": {
-			"uris": [
-				{
-					"id": "LINK_MODULE_URI_ID",
-					"uri": "http://maps.google.com/",
-					"description": "Link module URI description"
-				},
-				{
-					"id": "LINK_MODULE_TEL_ID",
-					"uri": "tel:6505555555",
-					"description": "Link module tel description"
-				}
-			]
-		},
-		"imageModulesData": [
-			{
-				"id": "IMAGE_MODULE_ID",
-				"mainImage": {
-					"contentDescription": {
-						"defaultValue": {
-							"value": "Image module description",
-							"language": "en-US"
-						}
-					},
-					"sourceUri": {
-						"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-					}
-				}
-			}
-		],
-		"textModulesData": [
-			{
-				"body": "Text module body",
-				"header": "Text module header",
-				"id": "TEXT_MODULE_ID"
-			}
-		],
-		"tripType": "ONE_WAY",
-		"id": "%s.%s"
-	}
-	`, issuerId, classSuffix, issuerId, objectSuffix)
-
-	var payload map[string]interface{}
+	transitJson, _ := json.Marshal(transitObject)
+	var payload map[string]any
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
-		"genericClasses": [%s],
-		"genericObjects": [%s]
+		"transitObjects": [%s]
 	}
-	`, newClass, newObject)), &payload)
-
+	`, transitJson)), &payload)
 	claims := jwt.MapClaims{
 		"iss":     d.credentials.Email,
 		"aud":     "google",
@@ -365,7 +212,7 @@ func (d *demoTransit) createJwtNewObjects(issuerId, classSuffix, objectSuffix st
 	key, _ := jwt.ParseRSAPrivateKeyFromPEM(d.credentials.PrivateKey)
 	token, _ := jwt.NewWithClaims(jwt.SigningMethodRS256, claims).SignedString(key)
 
-	fmt.Println("Add to Google Wallet link")
+	fmt.Println("Add to Google Wallet link for new objects")
 	fmt.Println("https://pay.google.com/gp/v/save/" + token)
 }
 
@@ -378,7 +225,7 @@ func (d *demoTransit) createJwtNewObjects(issuerId, classSuffix, objectSuffix st
 // their wallet, the pass objects defined in the JWT are added to the
 // user's Google Wallet app. This allows the user to save multiple pass
 // objects in one API call.
-func (d *demoTransit) createJwtExistingObjects(issuerId string) {
+func (d *demoTransit) createJwtExistingObjects(issuerId string, classSuffix string, objectSuffix string) {
 	var payload map[string]interface{}
 	json.Unmarshal([]byte(fmt.Sprintf(`
 	{
@@ -444,98 +291,20 @@ func (d *demoTransit) batchCreateObjects(issuerId, classSuffix string) {
 	for i := 0; i < 3; i++ {
 		objectSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 
-		batchObject := fmt.Sprintf(`
-		{
-			"classId": "%s.%s",
-			"passengerNames": "Passenger names",
-			"heroImage": {
-				"contentDescription": {
-					"defaultValue": {
-						"value": "Hero image description",
-						"language": "en-US"
-					}
-				},
-				"sourceUri": {
-					"uri": "https://farm4.staticflickr.com/3723/11177041115_6e6a3b6f49_o.jpg"
-				}
-			},
-			"ticketLeg": {
-				"destinationStationCode": "SFO",
-				"destinationName": {
-					"defaultValue": {
-						"value": "Destination name",
-						"language": "en-US"
-					}
-				},
-				"arrivalDateTime": "2020-04-12T20:20:50.52Z",
-				"originStationCode": "LA",
-				"originName": {
-					"defaultValue": {
-						"value": "Origin name",
-						"language": "en-US"
-					}
-				},
-				"departureDateTime": "2020-04-12T16:20:50.52Z",
-				"fareName": {
-					"defaultValue": {
-						"value": "Fare name",
-						"language": "en-US"
-					}
-				}
-			},
-			"barcode": {
-				"type": "QR_CODE",
-				"value": "QR code"
-			},
-			"locations": [
-				{
-					"latitude": 37.424015499999996,
-					"longitude": -122.09259560000001
-				}
-			],
-			"passengerType": "SINGLE_PASSENGER",
-			"state": "ACTIVE",
-			"linksModuleData": {
-				"uris": [
-					{
-						"id": "LINK_MODULE_URI_ID",
-						"uri": "http://maps.google.com/",
-						"description": "Link module URI description"
-					},
-					{
-						"id": "LINK_MODULE_TEL_ID",
-						"uri": "tel:6505555555",
-						"description": "Link module tel description"
-					}
-				]
-			},
-			"imageModulesData": [
-				{
-					"id": "IMAGE_MODULE_ID",
-					"mainImage": {
-						"contentDescription": {
-							"defaultValue": {
-								"value": "Image module description",
-								"language": "en-US"
-							}
-						},
-						"sourceUri": {
-							"uri": "http://farm4.staticflickr.com/3738/12440799783_3dc3c20606_b.jpg"
-						}
-					}
-				}
-			],
-			"textModulesData": [
-				{
-					"body": "Text module body",
-					"header": "Text module header",
-					"id": "TEXT_MODULE_ID"
-				}
-			],
-			"tripType": "ONE_WAY",
-			"id": "%s.%s"
+		transitObject := new(walletobjects.TransitObject)
+		transitObject.Id = fmt.Sprintf("%s.%s", issuerId, objectSuffix)
+		transitObject.ClassId = fmt.Sprintf("%s.%s", issuerId, classSuffix)
+		transitObject.State = "ACTIVE"
+		transitObject.PassengerNames = "Passenger names"
+		transitObject.TripType = "ONE_WAY"
+		transitObject.PassengerType = "SINGLE_PASSENGER"
+		transitObject.TicketLeg = &walletobjects.TicketLeg{
+			DestinationStationCode: "SFO",
+			OriginStationCode:      "LA",
 		}
-		`, issuerId, classSuffix, issuerId, objectSuffix)
+
+		transitJson, _ := json.Marshal(transitObject)
+		batchObject := fmt.Sprintf("%s", transitJson)
 
 		data += "--batch_createobjectbatch\n"
 		data += "Content-Type: application/json\n\n"
@@ -544,8 +313,7 @@ func (d *demoTransit) batchCreateObjects(issuerId, classSuffix string) {
 	}
 	data += "--batch_createobjectbatch--"
 
-	// batchUrl = 'https://walletobjects.googleapis.com/batch';
-	res, err := d.httpClient.Post(batchUrl, "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
+	res, err := d.credentials.Client(oauth2.NoContext).Post("https://walletobjects.googleapis.com/batch", "multipart/mixed; boundary=batch_createobjectbatch", bytes.NewBuffer([]byte(data)))
 
 	if err != nil {
 		fmt.Println(err)
@@ -558,11 +326,6 @@ func (d *demoTransit) batchCreateObjects(issuerId, classSuffix string) {
 // [END batch]
 
 func main() {
-	if len(os.Args) == 0 {
-		fmt.Println("Usage: go run demo_transit.go <issuer-id>")
-		os.Exit(1)
-	}
-
 	issuerId := os.Getenv("WALLET_ISSUER_ID")
 	classSuffix := strings.ReplaceAll(uuid.New().String(), "-", "_")
 	objectSuffix := fmt.Sprintf("%s-%s", strings.ReplaceAll(uuid.New().String(), "-", "_"), classSuffix)
@@ -574,6 +337,6 @@ func main() {
 	d.createObject(issuerId, classSuffix, objectSuffix)
 	d.expireObject(issuerId, objectSuffix)
 	d.createJwtNewObjects(issuerId, classSuffix, objectSuffix)
-	d.createJwtExistingObjects(issuerId)
+	d.createJwtExistingObjects(issuerId, classSuffix, objectSuffix)
 	d.batchCreateObjects(issuerId, classSuffix)
 }