CORS Unbound is a Firefox extension that bypasses CORS restrictions and rewrites HTTP request/response headers directly inside the browser. It is designed for local development, prototyping, automation, scraping, and advanced debugging — all without running a server. Features Automatic CORS Bypass Injects the appropriate Access-Control-* headers into responses based on the browser’s own CORS request headers. Header Rewriting Add, modify, or remove request and response headers using a rule-based UI. Rule System Each rule defines:

Origin URLs (the page making the request)
Target URLs (the request destination)
Header Actions (set/remove)
Resource Types (xmlhttprequest, sub_frame, script, image, websocket, etc.)

Learn more at: https://github.com/yobukodori/cors-unbound