Free API Tester Tool

Professional REST API testing tool for developers. Test endpoints, manage headers, authentication, request bodies. Import/export cURL commands, save requests, manage environments. No signup required – runs 100% client-side.

Key	Value	Enabled	Actions

Key	Value	Enabled	Actions

Body Headers Raw Preview

Why Use This Free API Tester in 2026

Testing APIs shouldn't require installing heavy desktop apps or creating accounts. Our free API tester runs entirely in your browser with these advantages:

100% client-side — your data never leaves your browser
No signup or registration required
Test any REST API with full control over headers, auth, body
Import/export cURL commands for easy sharing
Save requests and manage multiple environments
Dark mode support for comfortable long testing sessions
CORS-aware with clear error messages

Perfect for developers, QA engineers, and anyone working with APIs who wants a lightweight, privacy-focused testing tool.

How to Test APIs Effectively

Getting Started

Enter your API endpoint URL — Include the full URL with https://
Select the HTTP method — GET, POST, PUT, PATCH, DELETE, etc.
Add query parameters — Use the Params tab to add URL parameters
Configure headers — Add Content-Type, Accept, or custom headers
Set authentication — Choose from Basic Auth, Bearer Token, or API Key
Add request body — For POST/PUT requests, add JSON, XML, or form data
Click Send — View the response with status, headers, and body

Popular Use Cases

Testing REST APIs during development
Debugging API integration issues
Learning how APIs work
Verifying API authentication flows
Exploring third-party API documentation
Converting between cURL and fetch() code

Pro Tips

Use environment variables ({{VAR_NAME}}) for API keys and base URLs
Save frequently used requests for quick access
Check the browser console for detailed CORS error messages
Use the Format JSON button to make responses readable
Export as cURL to share requests with teammates
Press Ctrl+Enter (Cmd+Enter on Mac) to quickly send requests

Understanding CORS Restrictions

This tool runs in your browser, so it's subject to CORS (Cross-Origin Resource Sharing) restrictions. If you get CORS errors, the API server needs to allow requests from your domain. This is a browser security feature — it's not a limitation of this tool.

CORS-friendly APIs to test: JSONPlaceholder (jsonplaceholder.typicode.com), HTTPBin (httpbin.org), GitHub API (api.github.com), and many other public APIs.

Frequently Asked Questions

Is this API tester completely free?

Yes — 100% free forever. No signup, no credit card, no hidden costs. All processing happens in your browser.

Is my API data secure?

Absolutely. Everything runs client-side in your browser. We never see or store your requests, responses, API keys, or any other data. It's completely private.

Why am I getting CORS errors?

CORS errors occur when the API server doesn't allow cross-origin requests. This is a browser security feature. Try using a CORS-friendly API like JSONPlaceholder or HTTPBin for testing, or use a browser extension to disable CORS during development.

Can I test APIs that require authentication?

Yes! We support Basic Auth, Bearer Token, and API Key authentication. Configure these in the Authorization tab before sending your request.

How do I import a cURL command?

Click the "Import cURL" button, paste your cURL command, and we'll automatically parse it into the appropriate fields (method, URL, headers, body).

Can I save my requests?

Yes! Click the "Save" button to store requests locally in your browser. They'll be available in the "Saved Requests" sidebar for quick access.

What's the difference between this and Postman?

Postman is a powerful desktop application with team collaboration features. Our tool is simpler, runs in your browser, requires no installation or account, and is perfect for quick API testing without the overhead.

How do environment variables work?

Create variables like {{API_KEY}} in your URLs, headers, or body. Define the actual values in the Environments section. This makes it easy to switch between dev, staging, and production environments.

More developer tools? Check our full collection of free tools.