Why am I getting CORS errors?
Last checked 31 Aug 2026
Short answer
CORS errors happen when your app's domain tries to call an API that hasn't explicitly allowed it. Fix it on the server side — either by adding your domain to the API's allow-list or by routing the call through a server function.
What CORS is
Cross-Origin Resource Sharing (CORS) is a browser security rule: a webpage on domain A can't read a response from domain B's API unless domain B explicitly allows it. This is enforced by the browser, not something you can bypass from the front end.
Diagnostic sequence
- Open the browser console — a CORS error names the blocked origin and the API endpoint clearly.
- Identify who owns the API being called: a third-party service (Stripe, a public API) or your own backend (Supabase edge function).
- If it's your own Lovable Cloud/Supabase function, check that it returns the correct CORS headers — ask Lovable to confirm the function handles CORS.
- If it's a third-party API, check their documentation for how to configure allowed origins — some APIs aren't designed to be called directly from a browser at all.
Why this commonly happens in Lovable apps
- Calling a third-party API directly from front-end code instead of routing it through a server/edge function. Many APIs (and most that require a secret key) are not meant to be called from the browser, precisely because of CORS and security — secrets must live server-side.
- A custom edge function that doesn't explicitly set CORS headers for the app's published domain.
- Testing on a preview URL that isn't included in an API's allow-list, even though the production domain is.
Fixing it
I'm getting a CORS error calling [API/endpoint] from [page/component]. Move this call into a server function so it isn't made directly from the browser, and make sure that function returns the correct CORS headers.
What usually goes wrong
Trying to "fix" CORS with browser tricks or disabling security checks locally — this only masks the problem in your own testing and won't work for real users. The correct fix is always server-side: either the API allow-lists your domain, or you proxy the call through your own server function.
Sources
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