Firefox Developer Edition — Firefox.com
Firefox Developer Edition is the blazing fast browser that offers cutting edge developer tools and latest features like CSS Grid support and framework debugging
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Firefox Developer Edition is a specialized browser built for web developers, providing the latest DevTools features in beta to inspect, debug, and optimize web applications.
🚀 Overview
Firefox Developer Edition is a version of the Firefox browser tailored specifically for web developers. It runs alongside standard Firefox with a separate profile, offering developer-focused preferences like enabled remote debugging, dark theme, and developer toolbar by default. It delivers cutting-edge features and performance for building the open web.
- What problem does this project solve? It provides advanced, up-to-date developer tools to inspect, debug, and performance-tune web applications more efficiently than standard browsers.
- Who is it built for? Web developers who need powerful, beta-level DevTools.
- Why did you build it? To empower developers to create pixel-perfect sites and perfect their code with specialized tools and early access to new features.
Keep it human and honest.
✨ Key Features
- Inactive CSS: Grays out unused CSS declarations with explanations on hover, helping developers clean up styles.
- Multi-line Console Editor: Edit multiple lines of JavaScript directly in the console for faster debugging.
- WebSocket Inspector: Inspect and debug WebSocket connections in real-time.
- CSS Grid Tools: Visualize grids, display area names, and preview transforms.
- Fonts Panel: Quick access to font details like source, weight, and style.
- Responsive Design Mode: Test sites on emulated devices.
- Performance & Memory Tools: Identify bottlenecks, leaks, and optimize assets.
- Optional: Latest beta DevTools features as they land.
🛠 Tech Stack
- Browser Engine: Gecko (C++, Rust, JavaScript)
- DevTools Debugger: React, Redux
- Backend: Mozilla's rendering and JS engines
- Database: N/A (browser storage)
- Auth: N/A
- Hosting: Mozilla download servers, open-source builds
👥 Who Is This For?
This project is useful for:
- Developers who want to debug and inspect web apps with advanced tools
- Teams looking for beta access to Firefox DevTools
- Indie makers building modern web sites needing precise control
📸 Screenshots / Demo
- Live demo: https://www.mozilla.org/en-US/firefox/developer (download for all platforms)
- GitHub: https://github.com/mozilla/gecko-dev (source mirror), https://github.com/firefox-devtools/docs
🔥 Project Status
- 🟢 Actively building
Last updated: 2026-03-24
❓ FAQ
Is this project free?
Yes — Completely free and open source. (Explain briefly.)
Is the source code available?
Yes — Primary: https://hg.mozilla.org/mozilla-central/, GitHub mirror: https://github.com/mozilla/gecko-dev, DevTools docs: https://github.com/firefox-devtools/docs
Can I contribute?
Yes, help by filing bugs, writing code, fixing issues, or creating add-ons. Start at https://firefox-dev.tools/ or join discourse.mozilla.org/c/devtools for feedback and discussions.
📬 Contact & Links
- Website: https://www.mozilla.org/en-US/firefox/developer
- GitHub: https://github.com/mozilla
- Twitter/X: https://twitter.com/firefox
- Email: connect.mozilla.org
Built with ❤️ and kept warm on WarmIndex.
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