What causes a CORS error ?

Browser security blocks cross-origin fetches without proper headers like Access-Control-Allow-Origin.

How do I fix CORS in Vite or React dev?

Add a server proxy in vite.config.js to rewrite /api calls to your backend—no changes needed.

Yes, unless server-configured; use your own proxy endpoint to forward requests safely.

🌐 Frontend & Web

Your API call thrives in Postman, dies in the browser. CORS is the culprit—here's your five-minute escape plan.

theAIcatchup Apr 10, 2026 3 min read

CORS is browser-enforced security for cross-origin requests—fix via server headers or proxies. 𝕏
Use Vite/Webpack proxies in dev; build proxy routes for prod third-party APIs. 𝕏
Avoid hacks like disabling security—opt for cors() middleware with specific origins for safety. 𝕏

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Originally reported by dev.to