v0 API project_not_found error when fetching or deploying older projects

(edited)

I’m using v0 via the API, and since the latest update I’m running into issues accessing existing projects.

Problem

Older projects created before the latest update are no longer resolvable through the API, resulting in 404 errors during fetch or deployment operations.

Current Behavior

I can no longer fetch older projects by project ID or chat ID.
Those same projects also can’t be deployed via the API.
If I create a new project after the update, everything works fine (fetch + deploy).
The issue only affects projects created before the latest update.

Error Message

I get the following error when attempting to access older projects:

Error: Failed to fetch project: 404

{
  "error": {
    "code": "project_not_found_error",
    "type": "not_found_error",
    "message": "The project you're trying to access does not exist.",
    "userMessage": "This project does not exist. Please check the project ID and try again."
  }
}

Stack trace:

at try (app/(private)/test/_components/test-units.ts:26:15)

Is anyone else seeing this behavior?
Did something change around project IDs, chat IDs, or API access for older projects in the last update?

Would love to know if this is a known issue or if there’s a workaround.

Environment

Framework: Next.js 16

There's another community post with 404 debugging tips that might be helpful. Please give these solutions a try and let us know how it goes.

https://community.vercel.com/t/debugging-404-errors/437

Vercel Community

Debugging 404 Errors

Sometimes things don’t go as expected when deploying a website. If you see a 404 on your site, that means the page or resource couldn’t be found. There are...

A human should be around soon to offer more advice. But you can also get helpful information quickly by asking v0.

reply to #2

Thanks for the suggestions — I’ve gone through all of the linked debugging steps and none of them seem to apply in this case.

At this point, I’m trying to understand whether this behavior is expected or if it points to an issue on the API side:

The project IDs and chat IDs are unchanged and confirmed correct.
The same API calls work as expected for projects created after the latest update.
Only projects created before the update return project_not_found_error (404) when fetching or deploying via the API.
These projects still exist and were previously accessible, so this doesn’t appear to be a deletion or permissions issue on our end.

Given that scope, this feels less like a client-side or configuration problem and more like a regression or migration issue affecting older projects.

Can anyone confirm:

Whether access to pre-update projects via the API is currently a known issue?
If there was a change to how older project IDs or chat IDs are resolved?
Or if there’s a recommended workaround (e.g., migration, re-linking, or re-creation)?

Appreciate any clarification — happy to provide more details if needed.

reply to #6

Vercel Alum

Thanks for the detailed report!

You're experiencing this due to v0's major architectural update on February 4th where the platform migrated from the old v0 projects concept to a cleaner separation between folders (for organization) and actual Vercel Projects.

Here's what you can try:

Check if your older projects are still accessible through the v0 dashboard at v0.app/chat - they may exist but with different IDs
Use the v0 SDK's projects.list() method to enumerate all available projects and see if your older ones appear with new identifiers
As a workaround, you could export older projects from the UI (if accessible) and re-import them to get new IDs

Could you share a specific project ID or chat ID that's failing? This would help the engineering team investigate the ID mapping issue between legacy and new systems.

Thanks, I create a new Project and assign the chat to that project Its a workaround but it works

This topic is closed. It no longer accepts new replies.

{ "error": { "code": "project_not_found_error", "type": "not_found_error", "message": "The project you're trying to access does not exist.", "userMessage": "This project does not exist. Please check the project ID and try again." } }