REST API Client helps you test and debug APIs quickly and accurately, right in your browser. Whether you need to send http requests (get, post, put, delete) and inspect responses from your browser, this tool eliminatesintegration bugs, incorrect request formats, and protocol errors by giving you instant, reliable results. Every operation runs locally on your device — nothing is uploaded to any server, so your data stays completely private.
Key Features
All Methods
GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS requests.
Headers & Body
Custom headers, JSON/form-data bodies, and query parameter builder.
Response Inspector
View response status, headers, body with syntax highlighting.
History
Saved request history with the ability to replay.
Common Use Cases
- Test API endpoints during development without installing Postman or Insomnia
- Debug authentication flows by inspecting request and response headers
- Validate API responses with syntax-highlighted response bodies
REST API Client
Send HTTP requests (GET, POST, PUT, DELETE) and inspect responses from your browser.
Frequently Asked Questions
What is REST API Client?
REST API Client is an online API utility that send http requests (get, post, put, delete) and inspect responses from your browser. Features include All Methods, Headers & Body, Response Inspector. Requests are made directly from your browser, with full visibility into headers, status codes, and response bodies.
Testing APIs typically involves dedicated desktop applications or command-line tools that can be cumbersome to set up. REST API Client provides a lightweight browser-based alternative that requires no installation or configuration. Each request is transparent — you see exactly what is sent and received — making it ideal for quick debugging, exploring new endpoints, or demonstrating API behavior to team members.
Frequently Asked Questions
Can this tool make requests to any URL?
Yes, via a CORS proxy. Some non-CORS APIs may not work from the browser.
Are my requests logged?
Request history is stored locally in your browser only.
How does the All Methods feature work?
The All Methods feature get, post, put, patch, delete, head, and options requests. It is designed to be intuitive and responsive, giving you immediate feedback as you interact with the tool. All processing happens locally in your browser.
What is the benefit of headers & body?
Headers & Body custom headers, json/form-data bodies, and query parameter builder. This capability sets REST API Client apart from basic alternatives by providing more comprehensive functionality while maintaining the privacy and speed of local processing.
Is REST API Client really free to use?
Yes, REST API Client is completely free with no hidden charges, no sign-up requirements, and no usage limits. You can use it as often as you need, for any purpose — personal projects, commercial work, or educational use. There are no premium tiers or paid features.
Does REST API Client work on mobile devices?
Yes, it works on any device with a modern web browser — desktop, tablet, or phone. The interface is responsive and adapts to your screen size. Since all processing is done locally, you get the same performance regardless of your device.
What happens to my data when I use REST API Client?
Your data never leaves your device. Every operation is performed locally in your browser using JavaScript. No information is uploaded, stored, logged, or shared with any server. This privacy-first approach means you can work with sensitive data — passwords, API keys, personal information — without any risk of exposure.
Key Features
All Methods
GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS requests.
Headers & Body
Custom headers, JSON/form-data bodies, and query parameter builder.
Response Inspector
View response status, headers, body with syntax highlighting.
History
Saved request history with the ability to replay.
Common Use Cases
REST API Client is useful in a variety of scenarios across different workflows:
Test API endpoints during development without installing Postman or Insomnia
Debug authentication flows by inspecting request and response headers
Validate API responses with syntax-highlighted response bodies
Tips & Best Practices
Use environment variables for URLs
Store API base URLs and auth tokens in environment variables so you can quickly switch between dev, staging, and production.
Save common requests
Use the history feature to save and replay frequently used API requests for faster debugging.
Related Tools
Explore more api tools to enhance your workflow:
Request Builder
Build HTTP requests interactively and generate code snippets in multiple languages.
curl to Fetch Converter
Convert curl commands to JavaScript fetch, Python requests, and more.
HTTP Status Code Reference
Searchable reference of all HTTP status codes with descriptions and use cases.
WebSocket Tester
Connect to WebSocket endpoints, send messages, and inspect frames.
OpenAPI Validator
Validate OpenAPI 3.x and Swagger 2.0 specifications for correctness.
Mock API Generator
Generate mock API responses from JSON schemas for rapid development.
Common Errors & Fixes
Learn how to fix common errors related to REST API Client:
CORS Policy Blocked Request
Learn how to fix 'CORS policy: No Access-Control-Allow-Origin header' errors. Understand how CORS works and how to configure it correctly.
CORS Preflight Request Failed
Fix CORS preflight (OPTIONS) request failures. Learn how browsers check CORS permissions before making cross-origin requests.
400 Bad Request Error
Learn what 400 Bad Request means, common causes like malformed syntax or invalid request parameters, and how to fix them.
Invalid Content-Type Header Error
Fix 'Invalid Content-Type' errors when the request Content-Type header does not match the request body format.
422 Unprocessable Entity Error
Learn what 422 Unprocessable Entity means for API validation errors, how it differs from 400, and how to fix validation failures.
500 Internal Server Error
Learn what 500 Internal Server Error means, common causes, and how to debug and fix server-side failures.