CORS
Technology & Computing abbreviation · Internet & Web
| Stands for | Cross-Origin Resource Sharing |
|---|---|
| Categories | Technology & Computing |
CORS stands for Cross-Origin Resource Sharing, an Internet & web abbreviation.
A browser mechanism that lets a server declare, through HTTP headers such as Access-Control-Allow-Origin, which other websites may read its responses with JavaScript. Without those headers, the browser blocks scripts from reading cross-origin responses.
Example: The fetch call fails with a CORS error because the API doesn't allow our localhost origin.
Usage notes
CORS relaxes the same-origin policy in a controlled way rather than adding protection; it became a W3C Recommendation in 2014 and now lives in the WHATWG Fetch standard. Requests with custom headers or methods trigger a "preflight" OPTIONS request first. Only browsers enforce CORS, which is why the same request succeeds in curl or Postman. Pronounced like "cores".
Related abbreviations
More Internet & web abbreviations
- BEM – Block Element Modifier
- ccTLD – Country code top-level domain
- CDN – Content delivery network
- CGI – Common Gateway Interface
- CLS – Cumulative Layout Shift
- CMS – Content management system
- CSP – Content Security Policy
- CSR – Client-side rendering
- CSS – Cascading Style Sheets
- CWV – Core Web Vitals
- DOM – Document Object Model
- ES6 – ECMAScript 6