Deployed NextJS app's API returns 404

[nikolagigic]

Hey everyone,
So I've been struggling with this for past day and can't figure out why when I try to make a POST request to my API endpoint it keeps on returning 404 when the application is deployed on Vercel - it works perfectly fine locally.
I went through all checks and sorted them out if there were any on why my Serverless Function might not work and I still get the same issue.

Any idea why else could this happen?

Front-end is sending a Blob through FormData to back-end which then uses formidable to parse the file and perform side-effects with it. App is in Turborepo.

[chanmyaemaung]

Same to you. Did you solve? I am also stacked as the same like you'd facing this issues on the productions. Even is a just simple api routes but that returned as 404 not found in the production.

[kamenskiyyyy]

Maybe this is a problem in version 13? I also have this problem.

[saad-devx]

Hi, i am having the same issue, Pleassee help me if you figured it out somehow.

[nikolagigic]

The issue was not with API routes - the issue is that Vercel is masking unhandled exceptions to 404. So if something bad happens on back-end and you do not catch the exception AND returrn it to front-end you will never know what actually happened.

[AyushUnleashed]

Okay, so to fix this issue:

1. Handle exceptions better in the nextjs backend - your nextjs backend is doing some operation & failing at it on prod but not on local, it could be due to env issue. ( It was in my case )
2. once you fix the operation on your backend, it would work, it would give back response & 404 would go away.

[huisnotacouncillor]

Facing the same issue, it works most of the time, but sometimes it will return 404 page as the request's response, annoying.