Universal Web API Client
Universal Web API Client
100% Serverless HTTP/REST Tester
Hit Send to get a response.
Guide & Explanations
Universal Web API Client & REST Tester
Developing, testing, and automating API (Application Programming Interface) integrations has never been easier. Traditionally, developers had to install heavy desktop applications to execute and debug requests. Today, our 100% Serverless Web API Client allows you to do everything directly from your browser, with lightning-fast execution speed and total respect for privacy.
🚀 Multi-Protocol Features
Our tool is not limited to simple HTTP requests. It offers comprehensive support for modern protocols to meet all engineering needs:
- HTTP / REST: Create
GET,POST,PUT,DELETE, orPATCHrequests. Finely tune your headers, add URL parameters (query strings), and build complex request bodies (JSON, Form-Data, Plain text). - WebSockets: Establish real-time persistent connections. Listen to the server's message stream and send interactive data without refreshing the page.
- GraphQL: Benefit from a dedicated editor that analyzes your API's schema introspection to facilitate writing queries and mutations.
🔒 Local-First, Security, and Anti-CORS
One of the major challenges of API testing in a browser is the CORS (Cross-Origin Resource Sharing) restriction. Our application natively bypasses this limitation by offering a transparent proxy or interacting with CORS bypass extensions.
Your data remains private: your call history, request collections, and environment variables (access tokens, secret keys) are encrypted and saved locally via IndexedDB and LocalStorage. None of your sensitive data flows through our servers.
🛠️ No-Code Validation & Developer Toolkit
Save valuable time with our visual assertions panel:
- Automatically validate the status code (e.g.,
200 OK). - Verify that the response time is under 500ms.
- Ensure that a specific JSON key is present in the response body.
Finally, our built-in toolkit allows you to generate code snippets associated with your request in 1 click (cURL, JavaScript Fetch, Python Requests) or even analyze the content of a JSON Web Token (JWT).
Frequently Asked Questions
Q: Is Universal Web API Client free to use?
R: Yes, the Universal Web API Client utility is 100% free. All tools on Dolf.in are accessible at no cost and without intrusive ads.
Q: Is my data secure?
R: Absolutely. Dolf.in uses a 'Serverless' approach: your data is processed locally in your browser and is never sent to our servers.
Q: Do I need to install any software?
R: No, no download or installation is required. Everything works directly in your web browser.
Q: How does this tool handle CORS (Cross-Origin) errors?
R: Since this tool runs entirely in the browser, it can be blocked by CORS restrictions imposed by remote servers. To fix this, you can enable our transparent fallback Proxy from the settings, or install a browser extension that will inject the correct CORS headers on your API calls for 100% local operation.
Q: Where are my collections and variables stored?
R: Unlike heavy cloud platforms (like Postman), your data never leaves your machine. Everything (history, collections, environment variables) is saved in your browser via IndexedDB / LocalStorage for maximum speed and privacy.
Q: What protocols are supported?
R: Our client is multi-protocol: it natively supports the HTTP/REST standard (GET, POST, etc.) with all request body types, real-time connections via WebSockets, as well as GraphQL requests and Server-Sent Events (SSE).