CORS

Server rules that tell browsers which other sites may call it.

What is CORS?

CORS (Cross-Origin Resource Sharing) is how a server tells browsers which other websites may call it from JavaScript. Without the right headers, the browser blocks the response.

Access-Control-Allow-Origin: https://www.example.com
Access-Control-Allow-Methods: GET, POST

Level: Journeyman · More Web Development terms at this level

Updated September 27, 2026