Interactive API Client
Send HTTP requests with custom headers and body payloads directly from your browser.
Headers
Send a request to view response
What is this tool?
The API Client is a browser-native REST API testing suite and HTTP request builder. It allows developers to test endpoints using GET, POST, PUT, DELETE, PATCH, and HEAD methods, configure custom headers and query parameters, send JSON or text request bodies, and inspect status codes, response headers, and response payloads.
How to test REST API endpoints in the browser
- Select your HTTP method (GET, POST, PUT, DELETE, PATCH, or HEAD) from the dropdown.
- Enter the full target endpoint URL (e.g., https://api.example.com/v1/users).
- Add any required HTTP request headers (such as Authorization or Content-Type) or URL query parameters.
- If sending POST, PUT, or PATCH requests, enter your JSON or text payload in the Body tab.
- Click Send to dispatch the request directly from your browser and examine the returned response status, latency, headers, and body.
Key Features
- Supports standard HTTP methods: GET, POST, PUT, DELETE, PATCH, and HEAD
- Dynamic key-value editors for custom request headers and query parameters
- JSON syntax formatting and raw text request body support
- Real-time response inspection showing HTTP status code, response time in milliseconds, and payload size
- Formatted JSON response viewer with one-click copy functionality
- Direct browser fetch execution without middleman proxy servers
Frequently Asked Questions
Why did my API request fail with a CORS error?
Browsers enforce Cross-Origin Resource Sharing (CORS) security rules. If the target server does not include the appropriate 'Access-Control-Allow-Origin' header in its response, your browser will block the response from being read by client-side JavaScript.
Can I send custom authentication tokens or API keys?
Yes. You can add any custom header, such as 'Authorization: Bearer <token>' or 'x-api-key: <key>', in the Headers tab.
Is there an intermediate proxy server handling my requests?
No. Requests are dispatched directly from your browser using the native fetch() API. There is no intermediate backend proxy server reading or storing your traffic.
Can I test local development servers (e.g., localhost:3000)?
Yes, provided your local development server has CORS enabled or allows requests originating from browser clients.
Privacy First
Direct browser-to-server HTTP requests. When you send a request, your browser communicates directly with the target endpoint you specify. No intermediate proxy or logging server is used; target endpoints will receive your IP address, headers, and request payload as expected with standard HTTP requests.