Glossary coding Term Page
CORS
Browser rules that decide whether cross-origin responses can be read
Core Idea
CORS decides whether a frontend from one origin may read a response from another origin. The server may answer normally, but if the browser blocks access, JavaScript still cannot use the result.
Why It Matters Here
Mathbong uses CORS as the hub where FastAPI, frontend clients, cookies, and reverse-proxy deployments meet. Reading allowlists, credentials, and preflight behavior together is what makes browser-side failures understandable.