Firefox Developer Tools
Firefox Developer Tools: A capable free toolkit for developers debugging Firefox-based web applications. Ranked #142 of 145 in Web Browsers by our editors (3.0/10); pricing: Free plan; best for developers debugging Firefox-based web applications.
At a glance
- Editor score3.0 / 10
- PricingFree plan
- Best forDevelopers debugging Firefox-based web applications
- Free planYes
- Paid fromFree
- Browser engineGecko
- Facts checked21 Sep 2026
Where it wins
- Deep HTML, CSS, JavaScript, network, and performance inspection
- Storage, accessibility, responsive, and device-behavior testing
- Free, open-source desktop tooling across Windows, macOS, and Linux
Where it doesn't
- It is built into Firefox rather than a standalone browser product
- Deployment is desktop-focused, with mobile debugging handled remotely
- Support is centered on documentation and community channels
Our verdict on Firefox Developer Tools
Firefox Developer Tools is a free, open-source set of web development tools built into Firefox. It is designed for solo developers and teams working on Firefox-based web applications, including small, mid-market, and enterprise organizations. The toolkit covers HTML and CSS inspection, JavaScript debugging, network monitoring, performance analysis, storage inspection, accessibility testing, responsive layouts, and browser-level debugging. It can also connect to remote targets, including Firefox for Android, while its listed desktop platforms are Windows, macOS, and Linux.
Its strongest fit is for development and troubleshooting rather than everyday browsing. Page Inspector supports modifying HTML and CSS, while the JavaScript tools allow developers to step through code and inspect or modify runtime state. Network analysis, performance tools, and responsive testing bring several parts of the debugging workflow into one Firefox-based toolkit. Developers can also inspect cookies, local storage, IndexedDB, service workers, accessibility trees, add-ons, browser chrome, tabs, and workers. An MCP server adds an AI-assisted interaction option for the tools.
Firefox Developer Tools is a focused choice for teams that need detailed visibility into Firefox pages and browser behavior without a separate product cost. Its open-source model and free access suit a broad range of company sizes, but the product remains a component of Firefox rather than a standalone browser. Desktop deployment is central, with remote debugging extending coverage to Firefox for Android. Teams seeking Firefox-specific inspection, debugging, profiling, storage, accessibility, and responsive testing should find the scope well aligned; teams seeking a general-purpose daily browser product should look elsewhere.
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Firefox Developer Tools pricing
Firefox Developer Tools fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| Supported platforms | Desktop |
| Browser engine | Gecko |
| Built-in ad blocking | Not verified |
| Tracking protection | Not verified |
| Extension support | Not verified |
| Cross-device sync | Not verified |
| Open source | Yes |
| Deployment | Desktop |
| Platforms | Windows, macOS, Linux |
| Support | Community, Docs |
| Built for | Solo, Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | Free plan |
| Website | firefox-source-docs.mozilla.org |
| Facts checked | 21 Sep 2026 |
Alternatives to Firefox Developer Tools
- Google ChromeA complete free browser with broad platform coverage, sync, extensions, and built-in security.9.3
- Microsoft EdgeA free, cross-platform browser suited to Microsoft users who want broad compatibility.9.2
- Mozilla FirefoxA mature, privacy-focused browser for everyday browsing across desktop and mobile.9.1
See all Firefox Developer Tools alternatives →
Also Ranked In
Firefox Developer Tools is ranked in 2 of our directories.
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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