503 Errors When Calling External Groq API from Vercel Deployment

Hi everyone,

I’m experiencing an issue with my FastAPI backend deployed on Vercel where outbound API calls to the Groq API intermittently fail with 503 Service Unavailable errors.

Details:

  • The same API requests succeed 100% when made from my local development environment (status 200).
  • When deployed on Vercel, the requests intermittently return 503 errors with the message:
    { "error": { "message": "Service Unavailable", "type": "internal_server_error" } }
  • The request payload, headers, and API keys are consistent between local and deployed environments.
  • This problem started occurring recently without any code changes on my side.
  • I suspect the issue could be related to Vercel’s dynamic outbound IP ranges, rate limiting, or network restrictions.

Has anyone faced similar issues with outbound calls to third-party APIs? Are there known limitations on Vercel’s platform regarding external API connectivity? Any suggestions or recommended workarounds would be highly appreciated!

Thanks in advance!

— Pramod