diff --git a/examples/es-modules/README.md b/examples/es-modules/README.md
new file mode 100644
index 00000000..2bed2895
--- /dev/null
+++ b/examples/es-modules/README.md
@@ -0,0 +1,17 @@
+
+# Example with [ES modules](https://nodejs.org/api/esm.html)
+
+## How to use
+
+```
+# install the dependencies
+$ npm ci
+
+# start the server
+$ node server.js
+
+# start the client
+$ node client.js
+```
+
+You need Node.js `>=12.17.0`.
diff --git a/examples/es-modules/client.js b/examples/es-modules/client.js
new file mode 100644
index 00000000..23dcbf4b
--- /dev/null
+++ b/examples/es-modules/client.js
@@ -0,0 +1,18 @@
+import { Manager } from "socket.io-client";
+
+const manager = new Manager("ws://localhost:8080");
+const socket = manager.socket("/");
+
+socket.on("connect", () => {
+  console.log(`connect ${socket.id}`);
+});
+
+socket.on("disconnect", () => {
+  console.log(`disconnect`);
+});
+
+setInterval(() => {
+  socket.emit("ping", () => {
+    console.log("pong");
+  });
+}, 1000);
diff --git a/examples/es-modules/package-lock.json b/examples/es-modules/package-lock.json
new file mode 100644
index 00000000..9b1409d2
--- /dev/null
+++ b/examples/es-modules/package-lock.json
@@ -0,0 +1,238 @@
+{
+  "name": "es-modules",
+  "version": "1.0.0",
+  "lockfileVersion": 1,
+  "requires": true,
+  "dependencies": {
+    "@types/component-emitter": {
+      "version": "1.2.10",
+      "resolved": "https://registry.npmjs.org/@types/component-emitter/-/component-emitter-1.2.10.tgz",
+      "integrity": "sha512-bsjleuRKWmGqajMerkzox19aGbscQX5rmmvvXl3wlIp5gMG1HgkiwPxsN5p070fBDKTNSPgojVbuY1+HWMbFhg=="
+    },
+    "accepts": {
+      "version": "1.3.7",
+      "resolved": "https://registry.npmjs.org/accepts/-/accepts-1.3.7.tgz",
+      "integrity": "sha512-Il80Qs2WjYlJIBNzNkK6KYqlVMTbZLXgHx2oT0pU/fjRHyEp+PEfEPY0R3WCwAGVOtauxh1hOxNgIf5bv7dQpA==",
+      "requires": {
+        "mime-types": "~2.1.24",
+        "negotiator": "0.6.2"
+      }
+    },
+    "backo2": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/backo2/-/backo2-1.0.2.tgz",
+      "integrity": "sha1-MasayLEpNjRj41s+u2n038+6eUc="
+    },
+    "base64-arraybuffer": {
+      "version": "0.1.4",
+      "resolved": "https://registry.npmjs.org/base64-arraybuffer/-/base64-arraybuffer-0.1.4.tgz",
+      "integrity": "sha1-mBjHngWbE1X5fgQooBfIOOkLqBI="
+    },
+    "base64id": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/base64id/-/base64id-2.0.0.tgz",
+      "integrity": "sha512-lGe34o6EHj9y3Kts9R4ZYs/Gr+6N7MCaMlIFA3F1R2O5/m7K06AxfSeO5530PEERE6/WyEg3lsuyw4GHlPZHog=="
+    },
+    "better-assert": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/better-assert/-/better-assert-1.0.2.tgz",
+      "integrity": "sha1-QIZrnhueC1W0gYlDEeaPr/rrxSI=",
+      "requires": {
+        "callsite": "1.0.0"
+      }
+    },
+    "callsite": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/callsite/-/callsite-1.0.0.tgz",
+      "integrity": "sha1-KAOY5dZkvXQDi28JBRU+borxvCA="
+    },
+    "component-bind": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/component-bind/-/component-bind-1.0.0.tgz",
+      "integrity": "sha1-AMYIq33Nk4l8AAllGx06jh5zu9E="
+    },
+    "component-emitter": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/component-emitter/-/component-emitter-1.3.0.tgz",
+      "integrity": "sha512-Rd3se6QB+sO1TwqZjscQrurpEPIfO0/yYnSin6Q/rD3mOutHvUrCAhJub3r90uNb+SESBuE0QYoB90YdfatsRg=="
+    },
+    "cookie": {
+      "version": "0.4.1",
+      "resolved": "https://registry.npmjs.org/cookie/-/cookie-0.4.1.tgz",
+      "integrity": "sha512-ZwrFkGJxUR3EIoXtO+yVE69Eb7KlixbaeAWfBQB9vVsNn/o+Yw69gBWSSDK825hQNdN+wF8zELf3dFNl/kxkUA=="
+    },
+    "cors": {
+      "version": "2.8.5",
+      "resolved": "https://registry.npmjs.org/cors/-/cors-2.8.5.tgz",
+      "integrity": "sha512-KIHbLJqu73RGr/hnbrO9uBeixNGuvSQjul/jdFvS/KFSIH1hWVd1ng7zOHx+YrEfInLG7q4n6GHQ9cDtxv/P6g==",
+      "requires": {
+        "object-assign": "^4",
+        "vary": "^1"
+      }
+    },
+    "debug": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/debug/-/debug-4.1.1.tgz",
+      "integrity": "sha512-pYAIzeRo8J6KPEaJ0VWOh5Pzkbw/RetuzehGM7QRRX5he4fPHx2rdKMB256ehJCkX+XRQm16eZLqLNS8RSZXZw==",
+      "requires": {
+        "ms": "^2.1.1"
+      }
+    },
+    "engine.io": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-4.0.0.tgz",
+      "integrity": "sha512-WyTa1NJR8rRmPXGXNSSgA+XhzfYLVcRBjRoFx7gI3cARnEsyuMpg0PS/PMDnPMMQtkjmVZsi2/ETrpq4mhoYSw==",
+      "requires": {
+        "accepts": "~1.3.4",
+        "base64id": "2.0.0",
+        "cookie": "~0.4.1",
+        "cors": "~2.8.5",
+        "debug": "~4.1.0",
+        "engine.io-parser": "~4.0.0",
+        "ws": "^7.1.2"
+      }
+    },
+    "engine.io-client": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-4.0.0.tgz",
+      "integrity": "sha512-dmydBrbZW0AYX4+u7aRzslPw/MSZy3HwwqHx3Es5OPj9q0tnyPeFZZU/UE5aLjba6xIwZTXkB+OdqF5wmR21IA==",
+      "requires": {
+        "base64-arraybuffer": "0.1.4",
+        "component-emitter": "~1.3.0",
+        "debug": "~4.1.0",
+        "engine.io-parser": "~4.0.1",
+        "has-cors": "1.1.0",
+        "parseqs": "0.0.6",
+        "parseuri": "0.0.5",
+        "ws": "~7.2.1",
+        "xmlhttprequest-ssl": "~1.5.4",
+        "yeast": "0.1.2"
+      },
+      "dependencies": {
+        "parseuri": {
+          "version": "0.0.5",
+          "resolved": "https://registry.npmjs.org/parseuri/-/parseuri-0.0.5.tgz",
+          "integrity": "sha1-gCBKUNTbt3m/3G6+J3jZDkvOMgo=",
+          "requires": {
+            "better-assert": "~1.0.0"
+          }
+        },
+        "ws": {
+          "version": "7.2.5",
+          "resolved": "https://registry.npmjs.org/ws/-/ws-7.2.5.tgz",
+          "integrity": "sha512-C34cIU4+DB2vMyAbmEKossWq2ZQDr6QEyuuCzWrM9zfw1sGc0mYiJ0UnG9zzNykt49C2Fi34hvr2vssFQRS6EA=="
+        }
+      }
+    },
+    "engine.io-parser": {
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/engine.io-parser/-/engine.io-parser-4.0.1.tgz",
+      "integrity": "sha512-v5aZK1hlckcJDGmHz3W8xvI3NUHYc9t8QtTbqdR5OaH3S9iJZilPubauOm+vLWOMMWzpE3hiq92l9lTAHamRCg=="
+    },
+    "has-cors": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/has-cors/-/has-cors-1.1.0.tgz",
+      "integrity": "sha1-XkdHk/fqmEPRu5nCPu9J/xJv/zk="
+    },
+    "mime-db": {
+      "version": "1.44.0",
+      "resolved": "https://registry.npmjs.org/mime-db/-/mime-db-1.44.0.tgz",
+      "integrity": "sha512-/NOTfLrsPBVeH7YtFPgsVWveuL+4SjjYxaQ1xtM1KMFj7HdxlBlxeyNLzhyJVx7r4rZGJAZ/6lkKCitSc/Nmpg=="
+    },
+    "mime-types": {
+      "version": "2.1.27",
+      "resolved": "https://registry.npmjs.org/mime-types/-/mime-types-2.1.27.tgz",
+      "integrity": "sha512-JIhqnCasI9yD+SsmkquHBxTSEuZdQX5BuQnS2Vc7puQQQ+8yiP5AY5uWhpdv4YL4VM5c6iliiYWPgJ/nJQLp7w==",
+      "requires": {
+        "mime-db": "1.44.0"
+      }
+    },
+    "ms": {
+      "version": "2.1.2",
+      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
+      "integrity": "sha512-sGkPx+VjMtmA6MX27oA4FBFELFCZZ4S4XqeGOXCv68tT+jb3vk/RyaKWP0PTKyWtmLSM0b+adUTEvbs1PEaH2w=="
+    },
+    "negotiator": {
+      "version": "0.6.2",
+      "resolved": "https://registry.npmjs.org/negotiator/-/negotiator-0.6.2.tgz",
+      "integrity": "sha512-hZXc7K2e+PgeI1eDBe/10Ard4ekbfrrqG8Ep+8Jmf4JID2bNg7NvCPOZN+kfF574pFQI7mum2AUqDidoKqcTOw=="
+    },
+    "object-assign": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/object-assign/-/object-assign-4.1.1.tgz",
+      "integrity": "sha1-IQmtx5ZYh8/AXLvUQsrIv7s2CGM="
+    },
+    "parseqs": {
+      "version": "0.0.6",
+      "resolved": "https://registry.npmjs.org/parseqs/-/parseqs-0.0.6.tgz",
+      "integrity": "sha512-jeAGzMDbfSHHA091hr0r31eYfTig+29g3GKKE/PPbEQ65X0lmMwlEoqmhzu0iztID5uJpZsFlUPDP8ThPL7M8w=="
+    },
+    "parseuri": {
+      "version": "0.0.6",
+      "resolved": "https://registry.npmjs.org/parseuri/-/parseuri-0.0.6.tgz",
+      "integrity": "sha512-AUjen8sAkGgao7UyCX6Ahv0gIK2fABKmYjvP4xmy5JaKvcbTRueIqIPHLAfq30xJddqSE033IOMUSOMCcK3Sow=="
+    },
+    "socket.io": {
+      "version": "3.0.0-rc2",
+      "resolved": "https://registry.npmjs.org/socket.io/-/socket.io-3.0.0-rc2.tgz",
+      "integrity": "sha512-viH824jjAF+tCN6zfFgZR9wsgXWZ6zuVZ46ZQDsThyXdkv6+RihAZ/xz6LqsP8vFK83MVtRztMAIc56eyeKX0g==",
+      "requires": {
+        "base64id": "~2.0.0",
+        "debug": "~4.1.0",
+        "engine.io": "~4.0.0",
+        "socket.io-adapter": "2.0.3-rc1",
+        "socket.io-client": "3.0.0-rc2",
+        "socket.io-parser": "4.0.1-rc2"
+      }
+    },
+    "socket.io-adapter": {
+      "version": "2.0.3-rc1",
+      "resolved": "https://registry.npmjs.org/socket.io-adapter/-/socket.io-adapter-2.0.3-rc1.tgz",
+      "integrity": "sha512-/+irxVkiriDRMt2hcYYlDOl2LUU3wkjPQ1917t/hb617/W+bnlDaqEGqtQpFE/tWys5FI1+q2JnjdwNeRHxyNw=="
+    },
+    "socket.io-client": {
+      "version": "3.0.0-rc2",
+      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-3.0.0-rc2.tgz",
+      "integrity": "sha512-ZIVzV1ANogp5ZqkIn504UhD4NwZkCWLoq9/rHiNSI0RIsvsfGxyOzhNvr0fWPppfr8+hNt5Qbij6ucV5ijIJDg==",
+      "requires": {
+        "@types/component-emitter": "^1.2.10",
+        "backo2": "1.0.2",
+        "component-bind": "1.0.0",
+        "component-emitter": "~1.3.0",
+        "debug": "~4.1.0",
+        "engine.io-client": "~4.0.0",
+        "parseuri": "0.0.6",
+        "socket.io-parser": "4.0.1-rc2"
+      }
+    },
+    "socket.io-parser": {
+      "version": "4.0.1-rc2",
+      "resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-4.0.1-rc2.tgz",
+      "integrity": "sha512-aI20UWITf5vKgwA1HjCanYlM8cr2VDmOBiM3+1MM1MautnHAngiceuN0gUOtQs4MmWatuD2Td8g00EwHf3qthQ==",
+      "requires": {
+        "component-emitter": "~1.3.0",
+        "debug": "~4.1.0"
+      }
+    },
+    "vary": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/vary/-/vary-1.1.2.tgz",
+      "integrity": "sha1-IpnwLG3tMNSllhsLn3RSShj2NPw="
+    },
+    "ws": {
+      "version": "7.3.1",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-7.3.1.tgz",
+      "integrity": "sha512-D3RuNkynyHmEJIpD2qrgVkc9DQ23OrN/moAwZX4L8DfvszsJxpjQuUq3LMx6HoYji9fbIOBY18XWBsAux1ZZUA=="
+    },
+    "xmlhttprequest-ssl": {
+      "version": "1.5.5",
+      "resolved": "https://registry.npmjs.org/xmlhttprequest-ssl/-/xmlhttprequest-ssl-1.5.5.tgz",
+      "integrity": "sha1-wodrBhaKrcQOV9l+gRkayPQ5iz4="
+    },
+    "yeast": {
+      "version": "0.1.2",
+      "resolved": "https://registry.npmjs.org/yeast/-/yeast-0.1.2.tgz",
+      "integrity": "sha1-AI4G2AlDIMNy28L47XagymyKxBk="
+    }
+  }
+}
diff --git a/examples/es-modules/package.json b/examples/es-modules/package.json
new file mode 100644
index 00000000..b2db8765
--- /dev/null
+++ b/examples/es-modules/package.json
@@ -0,0 +1,15 @@
+{
+  "name": "es-modules",
+  "version": "1.0.0",
+  "description": "An example with ES modules (https://nodejs.org/api/esm.html)",
+  "type": "module",
+  "author": "Damien Arrachequesne",
+  "license": "MIT",
+  "engines": {
+    "node": ">=12.17.0"
+  },
+  "dependencies": {
+    "socket.io": "beta",
+    "socket.io-client": "beta"
+  }
+}
diff --git a/examples/es-modules/server.js b/examples/es-modules/server.js
new file mode 100644
index 00000000..3fffbee4
--- /dev/null
+++ b/examples/es-modules/server.js
@@ -0,0 +1,16 @@
+import { Server } from "socket.io";
+
+const io = new Server(8080);
+
+io.on("connect", (socket) => {
+  console.log(`connect ${socket.id}`);
+
+  socket.on("ping", (cb) => {
+    console.log("ping");
+    cb();
+  });
+
+  socket.on("disconnect", () => {
+    console.log(`disconnect ${socket.id}`);
+  });
+});