API Tester

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Test REST APIs with custom headers, query params, and request body

Developer

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About API Tester

API Tester is a powerful browser-based tool designed for developers to quickly test and debug REST APIs without leaving your workflow. Send requests with custom headers, query parameters, and request bodies, then inspect detailed responses in real-time to validate API behavior and troubleshoot integration issues.

Whether you are building integrations, debugging endpoints, or exploring third-party APIs, API Tester provides an intuitive interface to streamline your testing process. All processing happens locally in your browser, ensuring your API requests and sensitive data never leave your machine.

Local only

Privacy-safe

No setup

Instant testing

Full control

Custom requests

All methods

GET, POST, PUT, DELETE

How to use API Tester

Configure Your Request

Enter your API endpoint URL, select the HTTP method, add headers, query parameters, and request body as needed.

Send and Monitor

Click send to execute your request and watch the real-time response appear with full details including status, headers, and body.

Analyze and Iterate

Review the response, adjust your request parameters, and resend to refine your API integration until it works perfectly.

Pro Tips

Save frequently used API endpoints and header configurations as templates to test multiple requests faster.
Use the browser's developer console to debug JavaScript errors alongside your API responses for complete troubleshooting.
Test with different content-type headers (application/json, application/x-www-form-urlencoded) to ensure your API accepts various formats.
Export successful requests as curl commands or code snippets to quickly integrate them into your application or documentation.