How to connect to an external web API from a local Azure Function?

Question

I am trying to develop an Azure Function that makes calls to a web service on our Azure tenant. I can connect to the web service from Postman. However, when I try to run my Azure function in VSCode that attempts to connect to the same web service, I get a "TypeError: fetch failed" message with the cause "Error: unable to verify the first certificate". The error code is "UNABLE_TO_VERIFY_LEAF_SIGNATURE". For my local server, it is using https://localhost, and I start the function by using func start --useHttps --cert LocalCert.pfx --password ????????.

I have tried using several different modules, but I now I am trying to use the wretch APT, but still getting the same issue. Has anyone experienced this issue before?

Answer 1

Hello Shane Davis,

To resolve this issue, you can bypass Node.js certificate validation by adding an environment variable when starting the application. Specifically, you can add NODE_TLS_REJECT_UNAUTHORIZED=0

Please configure above environment variable app setting and let us know with an update.

If this answer was helpful, please click "Accept the answer" and mark Yes, as this can help other community members.

If you have any other questions or are still experiencing issues, feel free to ask in the "comments" section, and I'd be happy to help.