REST API Tester

Test REST APIs in your browser. Send GET/POST/PUT/PATCH/DELETE with query params, custom headers, Bearer/Basic/API-key auth, and inspect response headers, status, timing & size, a free Postman alternative.

Built and maintained by Shehzad Munir ·

Needs the internet: requests are relayed through our proxy. Nothing is stored after the request.

REST API Tester
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<a href="https://www.toolnova.org/dev-tools/api-tester">REST API Tester</a> by ToolNova

APA

ToolNova. (2026, September 5). REST API Tester [Online tool]. https://www.toolnova.org/dev-tools/api-tester

MLA

“REST API Tester.” ToolNova, 5 Sept. 2026, www.toolnova.org/dev-tools/api-tester.

Test REST APIs without leaving the browser

The REST API Tester sends GET, POST, PUT, and DELETE requests with custom headers and JSON bodies right from your browser, a lightweight, no-login alternative to Postman. Responses are beautified so you can read them at a glance.

Send GET, POST, PUT, PATCH, and DELETE requests with custom headers and body, then inspect the status, response, and timing. It's a lightweight alternative to heavier desktop clients for quickly checking an endpoint, reproducing a bug, or confirming an integration works.

Features

  • Query-param & custom-header builders
  • Bearer, Basic & API-key authentication
  • Response body, headers, status, time & size
  • Monaco JSON editor with pretty-printing
  • Recent-request history saved locally
  • Server-side proxy bypasses CORS

How to use REST API Tester

  1. 1

    Enter the endpoint

    Add the URL and choose an HTTP method.

  2. 2

    Set headers and body

    Add authentication headers and a JSON body if the request needs one.

  3. 3

    Send the request

    Fire it off and view the status and timing.

  4. 4

    Read the response

    Inspect the beautified JSON response and headers.

Common use cases

  • A developer verifies an endpoint returns the expected data.
  • A tester checks how an API responds to different payloads.
  • A student learns REST by making live requests.
  • An integrator confirms auth headers are accepted.

Detailed guide

Debug integrations faster

Verify authentication headers, experiment with request payloads, and read raw JSON responses to pin down exactly where a call breaks. Because it runs client-side, it's perfect for fast, ad-hoc checks during development without configuring a separate tool.

Frequently asked questions

How do I test a REST API online without Postman?

Enter your API endpoint URL, select the HTTP method (GET, POST, PUT, DELETE), add any required headers and request body, then click Send. The formatted JSON response appears instantly.

Can I add authentication headers to API requests?

Yes. Add Authorization headers (Bearer tokens, API keys, Basic auth) in the Headers section. Common headers like Content-Type and Accept are also supported.

Can I test my localhost API using this browser tool?

Yes. Since the tool runs directly in your browser, it can make requests to localhost (e.g., http://localhost:3000/api/users) and local network addresses. No CORS proxy needed for local APIs.

What HTTP methods does this API tester support?

Supports all standard HTTP methods: GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS. You can also send custom request bodies in JSON format for POST and PUT requests.

How is this different from Postman?

This tool works instantly in your browser with no installation, no account, and no configuration. Postman has more advanced features (collections, environments, tests), but for quick API testing, this is faster and simpler.

Can I test APIs that require OAuth or Bearer token authentication?

Yes. Add an Authorization header with value 'Bearer YOUR_TOKEN' in the Headers section. For OAuth 2.0, first obtain your access token using your OAuth provider, then paste it as the Bearer token here. Basic Auth can be added as 'Basic BASE64_OF_USER_PASS'.

How do I test an API without installing Postman?

Enter the endpoint URL, pick a method (GET, POST, PUT, DELETE), add headers or a body if needed, and send, all from your browser. You get the status code, timing and formatted response, with nothing to install.

Can I add authentication headers like a Bearer token?

Yes. Add custom headers including Authorization: Bearer <token> (or an API key header) so you can test authenticated endpoints directly.

Does it format and validate the JSON response?

Yes. The response body is pretty-printed and validated, and you see the status code and response time, so you can debug an endpoint quickly.

Can I add authentication headers?

Yes: add Bearer tokens or any custom headers your API requires before sending the request.

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