CORS Error
Your browser blocking a request because it looks suspicious.
What is CORS Error?
CORS (Cross-Origin Resource Sharing) is a security rule that stops websites from making requests to other domains without permission. When you see "CORS error" — your server needs to explicitly allow requests from your frontend's domain.
It's like a bouncer at a club. Your frontend shows up saying "I'm here to get data from this API," and the API's bouncer says "I don't have you on the list." The fix: add your frontend's domain to the list.
In Vibe Coding
CORS errors are one of the most common frustrations in vibe coding. They usually appear when your frontend (localhost:3000) tries to call an API on a different domain. The fix is adding the right headers on your server.
Example
For example: Your app at myapp.com tries to fetch data from api.example.com. The browser blocks it with a CORS error. The fix: api.example.com needs to add a header saying "I allow requests from myapp.com."
Why this matters
This matters because CORS Error appears repeatedly when building, deploying, debugging, or connecting services in vibe coding workflows.
When you'll hit this in practice
You will usually run into CORS Error when working on Error Fixer.