Test REST APIs directly in your browser — no install needed
Test REST APIs online free directly in your browser. Send GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS requests with custom headers and JSON body. View response status code, response body, and response time. Pretty-prints JSON responses automatically. No installation required, so it works as a lightweight alternative to Postman for quick endpoint checks, debugging public APIs, validating request payloads, and reviewing HTTP responses during development.
Testing APIs is a daily task for developers. While Postman is powerful, it requires installation and account creation. This browser-based tool lets you quickly test endpoints without any setup. It's perfect for quick checks during development, testing public APIs, verifying webhook endpoints, and demonstrating API behavior to teammates. The lightweight interface keeps you focused on the request and response without distractions.
Testing a GET endpoint: select GET, enter the URL, click Send. Testing authentication: add 'Authorization: Bearer your-token' in headers. Testing a POST endpoint: select POST, add Content-Type: application/json header, enter JSON body. Testing with query parameters: add them directly to the URL (e.g. ?page=1&limit=10). Handling CORS errors: the API server must allow browser requests — use a server-side proxy if needed.
Because this tester runs in the browser, requests are subject to CORS rules set by the target API. Some private APIs, internal networks, file uploads, cookies, or protected endpoints may require a server-side client, Postman, curl, or an authenticated environment. Use this tool for quick checks and lightweight debugging, then confirm critical API behavior in your normal development or QA workflow.
Use clear request headers such as Content-Type: application/json and Authorization when needed. Keep JSON bodies formatted before sending so errors are easier to spot. For GET endpoints, put query parameters directly in the URL. When a request fails, compare the browser result with server logs, API docs, and a command-line request to separate client-side CORS issues from real backend errors.
API Tester Online Free is useful when you need to complete a focused task quickly without installing desktop software, creating another account, or switching into a heavy workflow. It works well for quick checks, conversions, previews, cleanups, generation tasks, and everyday operations where speed and consistency matter. Test REST APIs online free directly in your browser. Send GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS requests with custom headers and JSON body. View response status code, response body, and response time. Pretty-prints JSON responses automatically. No installation required, so it works as a lightweight alternative to Postman for quick endpoint checks, debugging public APIs, validating request payloads, and reviewing HTTP responses during development.
Start with a small sample so you understand how API Tester Online Free handles your input, then apply it to the full task. Review the important fields, copy or export the result, and test it in the place where you plan to use it. This keeps the tool fast while still giving you a practical quality-control step before production use.
Yes, add an Authorization header with your token (e.g. 'Bearer your-token-here').
CORS errors occur when the API server doesn't allow requests from browser origins. This is a server-side restriction. Use a CORS proxy or test from a server environment.
Request history is not currently saved between sessions. Saving requests may be added in a future update.
GET retrieves data and has no body. POST sends data to create/update resources and includes a request body. Use GET for reading, POST for writing.
File upload (multipart/form-data) is not currently supported. This feature may be added in a future update.
Yes. API Tester Online Free is designed as a free browser-based utility for quick personal, learning, and professional workflows.
No. You can use API Tester Online Free directly in a modern browser such as Chrome, Edge, Safari, or Firefox.
Yes. The page is responsive and can be used on phones and tablets, although desktop is usually more comfortable for long input or repeated copy operations.
Use clean input, test with a small sample first, review the output carefully, and adjust any details that depend on your final use case.
In most cases, yes. You can use the generated or processed output in personal and commercial projects, but legal, financial, medical, or security-sensitive work should still be reviewed by a qualified person.
The tool is built for quick browser workflows. You should still avoid entering highly sensitive data unless the specific tool clearly states how the data is handled.
Many tools include copy or download actions. If a dedicated export is not available, you can usually copy the visible result manually.
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Tạo file .env và .env.example cho dự án.
Tạo .gitignore cho Node.js, Python, Java.
Tạo mock JSON data cho API testing.
Format và phân tích API response.
Test REST API: GET, POST, PUT, DELETE.
Giải thích regex, flags, capture group và cảnh báo pattern dễ lỗi.
Tạo OpenAPI JSON/YAML với params, auth và request body.
Chuyển đổi Binary, Hex, Base32.
Mã hóa/giải mã Base64.
Chuyển đổi Decimal, Binary, Hex.
Tạo CSS box-shadow trực quan.
Tính quyền file Linux.
