Online API Tester | Free REST Client

Introduction

Testing APIs shouldn't require installing heavy software like Postman or Insomnia. Our **Online API Tester** is a lightweight, browser-based REST client that lets you debug endpoints instantly. Whether you're checking a public API or testing your own backend, this tool has you covered.

How to Use the API Tester

1. **Select Method:** Choose the HTTP method (GET, POST, PUT, DELETE, etc.) from the dropdown
2. **Enter URL:** Paste the API endpoint you want to test
3. **Add Headers:** If required (e.g., Authorization tokens), switch to the 'Headers' tab and add key-value pairs
4. **Set Body:** For POST/PUT requests, switch to the 'Body' tab and enter your JSON payload
5. **Send:** Click the 'Send' button to execute the request
6. **Inspect:** View the status code, response time, and formatted JSON response below

Supported HTTP Methods

• **GET:** Retrieve data from a server
• **POST:** Submit data to create a new resource
• **PUT:** Update an existing resource
• **DELETE:** Remove a resource
• **PATCH:** Partially update a resource
• **HEAD:** Retrieve headers only
• **OPTIONS:** Describe communication options for the target resource

Understanding CORS

Because this tool runs entirely in your browser (client-side), it is subject to **Cross-Origin Resource Sharing (CORS)** policies. This means:

• You can test APIs that explicitly allow cross-origin requests (like many public APIs)
• If an API blocks browser requests, you might see a 'Network Error'
• For local development, ensure your backend is configured to allow requests from `localhost` or your current domain

Features

• **Zero Setup:** No installation or login required
• **Fast:** Lightweight client that loads instantly
• **Secure:** Requests go directly from your browser to the API; we don't see your data
• **Response Formatting:** Automatic JSON pretty-printing for readability

Start debugging your endpoints now with the **Online API Tester**!