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Architecture
API gateway vs reverse proxy vs CORS proxy: what each one does
API gateway vs reverse proxy vs CORS proxy compared: who each serves, what it does, where they overlap, and how to choose the right one for your architecture.
6 min read Read -
No-code
Calling APIs from no-code tools: Webflow, Bubble and Framer
Why API calls fail with CORS errors in no-code tools, which calls run in the browser and which on a server, and how to keep API keys out of your published site.
6 min read Read -
CORS
CORS preflight requests explained: when and why OPTIONS happens
What triggers a CORS preflight request, how the browser and server negotiate it, how Access-Control-Max-Age caches it, and how to fix the failures you'll see.
6 min read Read -
CORS
CORS with credentials: cookies, credentials: 'include' and the wildcard
Why cross-origin cookies need credentials: 'include', Access-Control-Allow-Credentials and an exact origin, how SameSite affects them, and why Vary matters.
5 min read Read -
CORS
CORS, CSP, CORP and COEP compared: browser security headers
CORS, CSP, CORP, COEP and COOP each answer a different question. Learn who sends each header, what it protects, and how they interact when a request fails.
5 min read Read -
CORS
Debugging CORS errors step by step in Chrome and Firefox DevTools
A repeatable routine for debugging CORS errors: read the console, find the preflight in the Network panel, compare headers, and reproduce the request with curl.
5 min read Read -
CORS
Fixing CORS errors in React and Vite, in dev and in production
Fix CORS errors in a React app built with Vite: set up server.proxy for development, understand why it vanishes in production, and choose a production fix.
5 min read Read -
CORS
Fixing CORS errors in SvelteKit and Astro
Where SvelteKit and Astro code runs decides whether CORS applies. Fix CORS errors with server endpoints, load functions, middleware, dev proxies or a proxy.
5 min read Read -
CORS
Fixing CORS errors in Vue and Nuxt: dev proxies, server routes and more
How to fix CORS errors in Vue and Nuxt: Vite's dev proxy for Vue, Nuxt server routes, routeRules proxies and Nitro devProxy, plus what works on static hosting.
5 min read Read -
CORS
How to fix 'No Access-Control-Allow-Origin header is present'
Read the exact CORS error, find out whose server has to change, and pick the right fix: configure the API, add a backend, use a dev proxy or a CORS proxy.
5 min read Read -
WebSockets
WebSockets and CORS: what the browser checks and how to proxy them
CORS does not apply to WebSockets. Learn what the Origin header does, how servers must check it, how to authenticate a socket, and how to proxy one safely.
5 min read Read -
CORS
What is CORS? A practical guide for frontend developers
Why browsers block cross-origin requests, how preflight works, how to read the CORS error in your console, and the three ways to fix it.
4 min read Read -
CORS
How to fix CORS errors in Next.js
Route handlers, rewrites, configuring the API, or a CORS proxy: which fix to use for an Access-Control-Allow-Origin error in a Next.js app, with code for each.
3 min read Read