Requestly

Intercept & Modify HTTP(s) Requests. Create Rules to Redirect, Add/Remove Headers, Mock APIs, Inject CSS/JS. Chrome & Firefox Extension 100,000+ active users

SaaS-based devtool available as a browser extension for Chrome, Firefox, Edge, and desktop app available for MacOS and Linux. Modify Headers, Redirect URLs, Switch Hosts, Mock API Response, Delay Network requests, Insert Custom Scripts, and much more.