Developer Tools Suite • Browser-Based API Workspace

API Testing Lab

Test APIs directly in your browser. Build, send, inspect, import and export API requests without installing a desktop API client.

Learn how to test an API online with our complete REST guide →

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API Testing Lab

Browser API Workspace

Paste cURL or URL → Configure Headers/Body → Send → Inspect Tree

Collections (1):

REST API Basics: CRUD & Variables

GETGet All Users

POSTCreate New Post

POSTGemini AI Generate Text

Final URL: https://generativelanguage.googleapis.com/v1beta/models/gemini-flash-latest:generateContent?key=AIzaSy_sample_key_123

Body Mode:

JSON Body Editor:

Response

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Click Send to get a response

Response headers, status codes, timing metrics, and interactive JSON tree will appear here.

Your API Testing Workspace, Right in the Browser

Build requests, add parameters and headers, send JSON bodies, inspect responses, and save your API requests — all from ToolJi. Works directly from your browser when the API allows browser requests.

1. Client-Side First

Requests execute directly from your browser when target APIs allow direct browser access, keeping data private and fast.

2. Response Inspection

View JSON tree structures, status codes, response headers, execution time in milliseconds, and raw text payloads.

3. Import & Export

Paste cURL commands to import request configurations instantly and export copyable Fetch, Axios, Python, and cURL code.

Frequently Asked Questions

What is an API Testing Lab?

API Testing Lab is a browser-based testing environment that allows developers to configure, send, inspect, import, and export REST API requests without installing desktop applications.

Can I test REST APIs in my browser?

Yes! You can test GET, POST, PUT, PATCH, and DELETE requests directly from your browser when the target API permits direct browser access.

Can I add headers and authentication?

Yes. You can add query parameters, custom HTTP headers, Bearer tokens, Basic Authentication (username/password), and API Key headers/query options.

Can I inspect JSON responses?

Yes. API Testing Lab features an interactive expandable JSON tree viewer, raw text viewer, header inspector, response status codes, and duration metrics.

Can I import and export API requests?

Yes. You can paste cURL commands to import request configurations instantly, save requests into local collection folders, and export client code for cURL, Fetch, Axios, Python, and PHP.

Why does CORS sometimes block an API request?

Browsers enforce Cross-Origin Resource Sharing (CORS) security. If a target API blocks direct browser access, ToolJi provides a secure, server-side proxy fallback so you can continue testing seamlessly.