Pass custom header to http endpoint via api gateway

Hi there.

I believe this could be achieved using Data Transformation. According to the documentation:

In API Gateway, an API's method request can take a payload in a different format from the integration request payload. Similarly, the backend may return an integration response payload different from the method response payload. You can map URL path parameters, URL query string parameters, HTTP headers, and the request body across API Gateway using mapping templates.

Please let me know if this helps.