Does this replace Postman?

For quick API testing in the browser, yes! For complex workflows, collections, and environment variables, Postman is still recommended.

Can I send cookies or auth tokens?

Yes — add them in the Headers section. For example: Authorization: Bearer your-token-here

What do I need to enter?

Just Headers and Request Body. Every field has a sensible default you can start from.

Is my data uploaded anywhere?

No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.

Does it work on a phone?

Yes. The layout adapts to small screens and needs no app or signup.

API Tester

Test HTTP APIs with any method, headers, and body. A lightweight Postman alternative.

100% free
Private in browser
No signup
No watermarks

HeadersOne per line: Key: Value

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About API Tester

API Tester on TheToolss is a lightweight HTTP client that lets you test any REST API endpoint. Send GET, POST, PUT, PATCH, DELETE requests with custom headers and body. View response status, headers, timing, and body — all in your browser.

How to use API Tester

Select the HTTP method and enter the API URL.
Add headers (optional) and request body for POST/PUT/PATCH.
Click Send and view the response details.

Key features

Supports GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS
Custom headers with easy key-value input
Request body support with auto JSON Content-Type detection
Response status, headers, body, timing, and size
Auto-formats JSON response bodies

Frequently asked questions

Does this replace Postman?: For quick API testing in the browser, yes! For complex workflows, collections, and environment variables, Postman is still recommended.
Can I send cookies or auth tokens?: Yes — add them in the Headers section. For example: Authorization: Bearer your-token-here
What do I need to enter?: Just Headers and Request Body. Every field has a sensible default you can start from.
Is my data uploaded anywhere?: No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
Does it work on a phone?: Yes. The layout adapts to small screens and needs no app or signup.

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