Description:

I’m setting up a webhook in Mailchimp to trigger events in my AWS Lambda function via API Gateway. When I enter the API Gateway endpoint URL as the callback URL in Mailchimp’s webhook setup, I consistently get a 404 error.

From Mailchimp’s documentation, I understand that the webhook sends data as application/x-www-form-urlencoded.

Current Setup:

API Gateway Integration:
Integration Type: Lambda Function
HTTP Method: POST

Request:

Can someone help me understand what might be causing the 404 error when Mailchimp attempts to verify my webhook URL? Are there specific configurations in API Gateway that I should check to ensure compatibility with application/x-www-form-urlencoded data from Mailchimp?

Any insights or guidance would be greatly appreciated. Thank you!

Reference docs: https://mailchimp.com/developer/marketing/guides/sync-audience-data-webhooks/