How to Use API Tester (REST Client)
A free, Postman-style REST API client that runs entirely in your browser. Choose the HTTP method, add query params, headers and authentication (Bearer or Basic), send a JSON, form or raw body, then inspect the status, timing, size, response headers and pretty-printed body. Because it runs in the browser it can call any API that allows cross-origin (CORS) requests — your tokens and data never leave your machine.
Open the API Tester (REST Client) tool →What is API Tester (REST Client)?
Test any REST API from your browser — set method, params, headers, auth and body, and inspect the response. It's completely free, needs no sign-up, and runs entirely in your browser — so it's fast and private.
How to use API Tester (REST Client)
- Open the API Tester (REST Client) tool.
- Paste or type your input.
- Set any options provided.
- Copy the result. Everything runs in your browser — nothing is uploaded.
Frequently asked questions
Is this a Postman alternative?
For quick REST testing in the browser, yes — set the method, params, headers, auth and body and inspect the response. The main difference is CORS (see below).
Why do some requests fail with a CORS error?
Because it runs in your browser, it can only call APIs that send cross-origin (CORS) headers — public APIs and your own APIs with CORS enabled. Postman's desktop app avoids this because it isn't a browser and makes requests from its own process.
Are my tokens and data safe?
Yes — requests go directly from your browser to the API. Nothing is proxied through our servers, so your URLs, tokens and responses never leave your machine.
Which methods and body types are supported?
GET, POST, PUT, PATCH, DELETE, HEAD and OPTIONS, with JSON, raw text, x-www-form-urlencoded and form-data bodies, plus Bearer and Basic auth.
Ready to try it?
Open API Tester (REST Client) →