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."