Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet. Fiddler allows you to inspect all HTTP(S) traffic, set breakpoints, and "fiddle" with incoming or outgoing data.

mitmproxy is an SSL-capable man-in-the-middle proxy for HTTP. It provides a console interface that allows traffic flows to be inspected and edited on the fly. It also features mitmdump, a commandline tool that provides a tcpdump-like interface for saving, viewing and...

The Google Chrome Developer Tools provide an integrated environment for debugging, optimizing, and understanding a web application, or website, running in Google Chrome. The developer tools are developed partly through the WebKit open source project, where the tools are called...

MultiGlancer is a minimalist and open-source tool I've developed to streamline the web development process. It allows developers to view their site on multiple web sizes simultaneously on a single screen. Born out of necessity while perfecting my landing page for ArcanePad.

Charles is an HTTP proxy / HTTP monitor / Reverse Proxy that enables a developer to view all of the HTTP and SSL / HTTPS traffic between their machine and the Internet. This includes requests, responses and the HTTP headers (which contain the cookies and caching information).

CodeTracer is a user-friendly time-traveling debugger designed to support a wide range of programming languages.

Cross-browser testing platform supporting over 3000 browser versions with real device cloud for iOS/Android, AI features for test creation, and HyperExecute for faster execution.

The Zed Attack Proxy (ZAP) is an easy to use integrated penetration testing tool for finding vulnerabilities in web applications.

Examine, edit, and debug HTML, CSS, and JavaScript on the desktop and on mobile.

Requestly is a lightweight proxy available as a browser extension & desktop app to intercept & modify network requests. Using Requestly you can Modify Headers, Redirect Url, Mock API response, Delay/Throttle requests, etc.

BrowserStack is the world’s largest cloud platform for software testing, with 20,000+ real Android and iOS devices that allow developers to comprehensively test their websites and apps for functionality, performance, and visual appeal.

The Web Developer extension adds various web developer tools to a browser. The extension is available for Chrome, Edge, Firefox, and Opera, and will run on any platform that these browsers support including Windows, macOS and Linux.

Develop responsive web apps 5x faster! A must-have DevTool for all Front-End developers that will make your job easier.

Sorry Cypress is an open-source platform that serves as an alternative to the Cypress Cloud

Debug, troubleshoot and analyse parallel CI tests in Cloud. A drop-in replacement for Cypress Dashboard. Now supporting Playwright.