Rex — API Client

Rex is a full-featured API client that lives in your browser. Test REST APIs, GraphQL endpoints, WebSockets, and Server-Sent Events without switching to a separate app. If you've ever wished Postman was just a tab away, Rex is for you.

Built for developers who spend their day in the browser — debugging frontend requests, testing backend endpoints, or exploring third-party APIs. Open Rex as a new tab or from DevTools, and you're ready to go. No account required, no cloud sync, no sign-up wall. Everything stays local on your machine.

WHY REX?

Most API clients are heavyweight desktop apps or cloud-first tools that require accounts and subscriptions just to send a GET request. Rex takes a different approach: it's a browser extension that's always one click away, stores everything locally in IndexedDB, and gives you professional-grade tooling without the overhead.

Because Rex runs inside Chrome, it has access to things external tools don't — your browser cookies, your active sessions, your DevTools network requests. That means you can test authenticated APIs without manually copying tokens, inspect cookies per domain, and import requests straight from the Network tab.

WHAT YOU CAN DO WITH REX