diff --git a/apps/sim/app/api/webhooks/trigger/[path]/route.ts b/apps/sim/app/api/webhooks/trigger/[path]/route.ts
index 549ce6a78..9cdff87dc 100644
--- a/apps/sim/app/api/webhooks/trigger/[path]/route.ts
+++ b/apps/sim/app/api/webhooks/trigger/[path]/route.ts
@@ -5,6 +5,7 @@ import {
   checkWebhookPreprocessing,
   findWebhookAndWorkflow,
   handleProviderChallenges,
+  handleProviderReachabilityTest,
   parseWebhookBody,
   queueWebhookExecution,
   verifyProviderAuth,
@@ -123,6 +124,11 @@ export async function POST(
     return authError
   }
 
+  const reachabilityResponse = handleProviderReachabilityTest(foundWebhook, body, requestId)
+  if (reachabilityResponse) {
+    return reachabilityResponse
+  }
+
   let preprocessError: NextResponse | null = null
   try {
     preprocessError = await checkWebhookPreprocessing(foundWorkflow, foundWebhook, requestId)
diff --git a/apps/sim/lib/webhooks/processor.ts b/apps/sim/lib/webhooks/processor.ts
index b197a8ef1..96cf01b8f 100644
--- a/apps/sim/lib/webhooks/processor.ts
+++ b/apps/sim/lib/webhooks/processor.ts
@@ -121,6 +121,34 @@ export async function handleProviderChallenges(
   return null
 }
 
+/**
+ * Handle provider-specific reachability tests that occur AFTER webhook lookup.
+ *
+ * @param webhook - The webhook record from the database
+ * @param body - The parsed request body
+ * @param requestId - Request ID for logging
+ * @returns NextResponse if this is a verification request, null to continue normal flow
+ */
+export function handleProviderReachabilityTest(
+  webhook: any,
+  body: any,
+  requestId: string
+): NextResponse | null {
+  const provider = webhook?.provider
+
+  if (provider === 'grain') {
+    const isVerificationRequest = !body || Object.keys(body).length === 0 || !body.type
+    if (isVerificationRequest) {
+      logger.info(
+        `[${requestId}] Grain reachability test detected - returning 200 for webhook verification`
+      )
+      return NextResponse.json({ status: 'ok', message: 'Webhook endpoint verified' })
+    }
+  }
+
+  return null
+}
+
 export async function findWebhookAndWorkflow(
   options: WebhookProcessorOptions
 ): Promise<{ webhook: any; workflow: any } | null> {