{ "schema_version": 2, "slug": "firefox-developer-edition-en-us", "name": "Firefox Developer Edition (en-US)", "publisher": "Mozilla", "author": "Mozilla Foundation", "ids": { "winget": "Mozilla.Firefox.DeveloperEdition", "moniker": "firefox-dev", "homebrew_cask": "firefox@developer-edition" }, "platforms": [ "windows", "macos" ], "summary": "Firefox Browser Developer Edition", "description": "Get the latest features, fast performance, and the development tools you need to build for the open web using Firefox Browser Developer Edition.", "tags": [ "browser", "cross-platform", "foss", "gecko", "quantum", "spidermonkey", "web", "web-browser" ], "locale": "en-US", "urls": { "homepage": "https://www.mozilla.org/firefox/developer/", "publisher": "https://www.mozilla.org/", "support": "https://support.mozilla.org/", "privacy": "https://www.mozilla.org/privacy/firefox/", "release_notes": "https://www.firefox.com/en-US/firefox/156.0beta/releasenotes/" }, "license": { "name": "MPL-2.0", "url": "https://www.mozilla.org/MPL/2.0", "spdx": "MPL-2.0", "copyright_url": "https://www.mozilla.org/foundation/trademarks/policy" }, "pricing": { "status": "open-source", "source": "derived-from-license" }, "latest_versions": { "windows": "156.0", "macos": "160.0b5" }, "last_updated": "2026-09-02", "versions_total": { "windows": 195, "macos": 1 }, "versions": [ { "platform": "windows", "version": "156.0", "release_date": "2026-09-02", "release_notes": "Version 156.0beta, first offered to Beta channel users on August 31, 2026\nFirefox Beta gets updated 3 times a week and as a consequence, the release notes for the Beta channel are updated continuously to reflect features that have reached sufficient maturity to benefit from community feedback and bug reports.\nWarning: Features listed here may or may not make a final release of Firefox.\nIn addition to these release notes, you can follow ongoing development via the Firefox Trains website or our @FirefoxBeta Bluesky account.\n\nNew\n- macOS users can now configure Firefox to launch automatically at startup via Settings.\n- Improved memory and CPU usage when Firefox displays large JPEG images scaled down to fit a page.\n- Localized Wikipedia and occasional sponsored suggestions in the address bar now available in France, Germany, and Italy (can be disabled in Firefox Suggest settings).\n- Firefox for Android media notifications now include previous/next buttons and timeline seeking controls.\n- Firefox for Android sharing now uses native Android share sheet on Android 14+, with options like Send tab to device and Scan QR code.\n\nFixed\n- Windows ARM64 devices: WebRTC video calls may now use hardware H264 decoding.\n- Fixed dragging an inline image to a new position in a rich-text editor replacing it with a long line of text instead of moving it.\n- All devices: WebRTC video calls may now use hardware AV1 decoding.\n- Fixed high-sample-rate FLAC audio in MP4 failing to play on sites such as Bilibili.\n- Fixed find bar becoming permanently unavailable after reversing panes in Split View.\n- Windows: fixed Firefox blocking auto-hiding taskbars.\n- Firefox for Android: fixed crashes when selecting files from certain Android file providers.\n- Fixed subtitles not appearing in Picture-in-Picture after being enabled post-launch.\n- Firefox for Android: fixed date picker allowing dates before minimum when maximum was specified.\n\nChanged\n- Firefox's built-in PDF viewer now starts up to 45% faster.\n\nEnterprise\n- FirefoxHome policy now includes Widgets option for controlling new tab productivity widgets.\n- SitePolicies policy now supports DisableServiceWorkers for blocking service worker registration.\n- Windows installer now resolves /INI= paths relative to installer location.\n- Fixed DontCheckDefaultBrowser and DefaultBrowserSettingEnabled policies being ignored on new profiles.\n\nWeb Platform\n- text-box-trim now uses font metrics of ::first-line pseudo-elements when applicable.", "release_notes_url": "https://www.firefox.com/en-US/firefox/156.0beta/releasenotes/", "manifest_version": "1.12.0", "manifest_dir": "manifests/m/Mozilla/Firefox/DeveloperEdition/156.0", "installers": [ { "platform": "windows", "architecture": "x86", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/156.0b2/win32/en-US/Firefox%20Setup%20156.0b2.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 156.0b2.exe", "sha256": "66d6910eb8e80b1a6b28c894710d9789af3f9d9b9ea96f972742ae2a4d3ff613", "product_code": "Firefox Developer Edition", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] }, { "platform": "windows", "architecture": "x64", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/156.0b2/win64/en-US/Firefox%20Setup%20156.0b2.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 156.0b2.exe", "sha256": "16474c74b4c8456f283e2bbdc53ce1689582a816ae100555c459d6aebbecce8d", "product_code": "Firefox Developer Edition", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] }, { "platform": "windows", "architecture": "arm64", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/156.0b2/win64-aarch64/en-US/Firefox%20Setup%20156.0b2.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 156.0b2.exe", "sha256": "8a54f365080466fe0e3072588ff1b047c2350ea8b937d195b500b184c2655c2e", "product_code": "Firefox Developer Edition", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] } ] }, { "platform": "windows", "version": "151.0", "release_date": "2026-05-13", "release_notes": "Version 151.0beta, first offered to Beta channel users on April 22, 2026\nFirefox Beta gets updated 3 times a week and as a consequence, the release notes for the Beta channel are updated continuously to reflect features that have reached sufficient maturity to benefit from community feedback and bug reports.\nWarning: Features listed here may or may not make a final release of Firefox.\nIn addition to these release notes, you can follow ongoing development via the Firefox Trains website or our @FirefoxBeta Bluesky account.\n\nNew\n- On macOS, URLs copied from iOS devices using Apple’s Universal Clipboard now paste correctly in Firefox.\n- HTML elements with an associated , displaying the autofill dropdown. See documentation.\n- The functions xywh() and rect() were previously already implemented for the clip-path and offset-path properties. Now they are also available for the shape-outside property.\n- The math value of the CSS font-family is now supported and used by default for MathML's element. It enables Web developers to indicate special fonts with advanced math features should be used. Firefox will rely on the serif font for mathematics defined in Firefox preferences.\n- Added support for the HTML attribute popover=\"hint\".\n- Enabled media element pseudo-classes, such as :playing, :paused…\n- Enabled the spec-compliant HTMLMediaElement.captureStream() API.\n- Added support for closing popovers & dialogs with the Android Back Button, and implement the CloseWatcher API for handling this in script.\n- The new Reporting API provides a generic reporting mechanism for web applications to use to make reports available based on various platform features (for example Content Security Policy, Permissions-Policy, or feature deprecation reports) in a consistent manner.", "release_notes_url": "https://www.firefox.com/en-US/firefox/149.0beta/releasenotes/", "manifest_version": "1.12.0", "manifest_dir": "manifests/m/Mozilla/Firefox/DeveloperEdition/149.0", "installers": [ { "platform": "windows", "architecture": "x86", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/149.0b8/win32/en-US/Firefox%20Setup%20149.0b8.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 149.0b8.exe", "sha256": "fd25b9afb4f87b42169aff96ac19084bf803256a0122fcd00c8065fa5a03b12b", "product_code": "Firefox Developer Edition", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] }, { "platform": "windows", "architecture": "x64", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/149.0b8/win64/en-US/Firefox%20Setup%20149.0b8.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 149.0b8.exe", "sha256": "b52f15d967c8732452b5fd811fd11a04cfbeb7080dd7a9b307bfbd20e5541bfb", "product_code": "Firefox Developer Edition", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] }, { "platform": "windows", "architecture": "arm64", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/149.0b8/win64-aarch64/en-US/Firefox%20Setup%20149.0b8.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 149.0b8.exe", "sha256": "316c53b2754adf514d5208d6fa2364b400034620907eb3470a5a6fc5e7f0cb4f", "product_code": "Firefox Developer Edition", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] } ] }, { "platform": "windows", "version": "148.0", "release_notes": "New\n- Firefox now has improved support for screen readers accessing mathematical formulas embedded in PDFs.\n- Firefox for Android introduces a refreshed toolbar with a modern design and improved customization support.\n- Firefox for Android now includes a \"Copy link text\" context menu item to copy the text associated with a link.\n- Added an AI Controls section to Settings for managing AI-enhanced features.\n Coming in 148.0 Beta 11\n\nFixed\n- On Windows, dragging a downloaded image to Adobe Illustrator now properly drops an image instead of the image's URL.\nDeveloper\n\nWeb Platform\n- The initial empty document is now Web-compatible: if the first navigation of a browsing context goes to about:blank, it completes synchronously and is no longer replaced by a second parser-generated document.\n- Firefox now supports the Trusted Types API, which is primarily aimed at preventing cross-site scripting attacks.\n- Firefox now supports the CSS shape() function, which allows defining responsive free-form shapes in properties that take shapes like clip-path. It has some advantages over the path() function, as it utilizes standard CSS syntax, supports various CSS units, and enables the use of mathematical functions.\n- Firefox now supports the Sanitizer API, which provides new methods for HTML manipulation. The element.setHTML() method enables developers to insert HTML content similarly to element.innerHTML, but without the security vulnerabilities such as cross-site scripting (XSS). A complementary method, document.parseHTML(), is also available for parsing HTML safely.\n- The joint iteration proposal adds new Iterator.zip and Iterator.zipKeyed methods that allow zipping together underlying iterators into an iterator over values grouped by position, similar to zip in many other languages.\n- Firefox now supports the position-try-order property, which is part of CSS Anchor Positioning and allows changing the order in which position fallback options are tried.\n- Service worker support for WebGPU has been added, making it available in all worker contexts. Service workers allow WebGPU to run in the background, which is particularly useful for extensions and other pages that can meaningfully share resources across multiple tabs and time periods.\n- Firefox now supports the location.ancestorOrigins attribute.", "release_notes_url": "https://www.mozilla.org/firefox/148.0beta/releasenotes/", "manifest_version": "1.12.0", "manifest_dir": "manifests/m/Mozilla/Firefox/DeveloperEdition/148.0", "installers": [ { "platform": "windows", "architecture": "x86", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/148.0b13/win32/en-US/Firefox%20Setup%20148.0b13.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 148.0b13.exe", "sha256": "93e282ffdc3fa4dac624bb264b845007631854f11fa40b3e8e1022a5303386a4", "product_code": "Firefox Developer Edition 148.0 (x86 en-US)", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] }, { "platform": "windows", "architecture": "x64", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/148.0b13/win64/en-US/Firefox%20Setup%20148.0b13.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 148.0b13.exe", "sha256": "0d9e08673a9ab1ee0a385bdc7f1648fb2913bd22fa29606011e640271bf2b6e5", "product_code": "Firefox Developer Edition 148.0 (x64 en-US)", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] }, { "platform": "windows", "architecture": "arm64", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/148.0b13/win64-aarch64/en-US/Firefox%20Setup%20148.0b13.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 148.0b13.exe", "sha256": "865dfd0b825046e7208d56314e547ff9db26c3fbab765b86d2de19d0b26989b3", "product_code": "Firefox Developer Edition 148.0 (arm64 en-US)", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] } ] }, { "platform": "windows", "version": "147.0", "release_date": "2025-12-22", "release_notes": "New\n- WebGPU support is now enabled for all macOS versions on devices with Apple Silicon processors.\n- Zero copy video of hardware decoded video with AMD GPUs if supported, improving video playback performance on those systems.\n- Firefox now supports the Freedesktop.org XDG Base Directory Specification.\n- Firefox now supports the Safe Browsing V5 protocol and is migrating from Safe Browsing V4 to the local list mode of Safe Browsing V5 protocol.\n- We've added a new feature to automatically open a Picture-in-Picture player window for a playing video in a tab if that tab is ever backgrounded. This feature was mainly contributed by a volunteer Daniele Ferla, and has recently graduated from Firefox Labs! You can turn this feature on by visiting about:settings and checking \"Keep playing videos in Picture-in-Picture when switching tabs\".\n- Firefox 147 includes support for Compression Dictionaries, IETF RFC 9842. This can significantly reduce the number of bytes transferred to load a page in several ways. That can lead to faster pageloads, especially for users with restricted bandwidth. Several major sites are currently using this, and likely many more will in the next year.\nFixed\n- A draggable button is now draggable if the drag is started from the button itself.\n- Fixed an issue that prevented Windows users from selecting a tab when the cursor was at the top of the screen and Firefox was maximized on some kinds of monitors.\n- For Linux GNOME Mutter users, window and rendering surface sizes were updated to match the actual pixel grid so Firefox delivers sharp rendering on fractionally scaled displays regardless of actual window size.\n- Fixed a bug that made HTTP/3 requests containing non-UTF-8 header values time out or fallback to HTTP/2 after awhile.\nChanged\n- Firefox now uses the same quality values (q-values) in Accept-Language headers as other major browsers. The second language preference is now sent with q=0.9 instead of q=0.5, with subsequent languages decreasing by 0.1 each (minimum 0.1). This change fixes compatibility issues with some servers that incorrectly rejected requests with lower quality values.\nDeveloper\n\nWeb Platform\n- Added support for the Navigation API. This API provides the ability to initiate, intercept, and manage browser navigation actions. It is a successor to previous web platform features such as the History API and window.location, which solves their shortcomings.\n- The CSS counter-* and quotes properties are now supported in the ::marker pseudo-element.\n- Both CompressionStream and DecompressionStream now support the Brotli format.\n- Firefox now exposes the view transition currently active on the document via the Document.activeViewTransition property.\n- Firefox now supports the :active-view-transition-type selector and associated View Transitions API changes.\n- CSS Module Scripts allow stylesheets to be imported using the JavaScript module system and import attributes, for more information, please see https://developer.mozilla.org/docs/Web/JavaScript/Guide/Modules#loading_non-javascript_resources.\n- Support for CSS anchor positioning was added, which allows to tether elements together. The anchor-positioned elements can then have their size and position set relative to the size and location of the anchor elements to which they are bound.\n- Firefox now supports Storage-Access-Headers allowing servers to opt-in into unpartitioned cookies via HTTP headers if storage-access was granted prior with the Storage-Access-API.\n- Module service workers are now supported, aligning Firefox with other major browsers and improving compatibility for modern web apps.\n- Implemented CSS root-font-relative units rcap, rch, rex and ric.", "release_notes_url": "https://www.mozilla.org/firefox/147.0beta/releasenotes/", "manifest_version": "1.10.0", "manifest_dir": "manifests/m/Mozilla/Firefox/DeveloperEdition/147.0", "installers": [ { "platform": "windows", "architecture": "x86", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/147.0b7/win32/en-US/Firefox%20Setup%20147.0b7.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 147.0b7.exe", "sha256": "19a6bb45abc6f60093c1e22fd84cebd60e9e972b091a70b47a3a620e1474e32f", "product_code": "Firefox Developer Edition 147.0 (x86 en-US)", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] }, { "platform": "windows", "architecture": "x64", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/147.0b7/win64/en-US/Firefox%20Setup%20147.0b7.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 147.0b7.exe", "sha256": "f758f00350740cbb9c48a38029f5ed3f2f3cf00d1145d9b2b9d516b2a9651f9f", "product_code": "Firefox Developer Edition 147.0 (x64 en-US)", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] }, { "platform": "windows", "architecture": "arm64", "type": "nullsoft", "scope": "machine", "url": "https://download-installer.cdn.mozilla.net/pub/devedition/releases/147.0b7/win64-aarch64/en-US/Firefox%20Setup%20147.0b7.exe", "host": "download-installer.cdn.mozilla.net", "filename": "Firefox Setup 147.0b7.exe", "sha256": "9984dfc05645a00c688a32a0290175390264633d2cb8fec867ad5c44905589ae", "product_code": "Firefox Developer Edition 147.0 (arm64 en-US)", "switches": { "silent": "/S /PreventRebootRequired=true", "silent_with_progress": "/S /PreventRebootRequired=true", "install_location": "/InstallDirectoryPath=\"\"" }, "upgrade_behavior": "install", "protocols": [ "http", "https", "mailto" ], "file_extensions": [ "avif", "htm", "html", "pdf", "shtml", "svg", "webp", "xht", "xhtml" ] } ] }, { "platform": "windows", "version": "146.0", "release_date": "2025-11-28", "release_notes": "New\n- When a website uses a file upload field (

elements, regardless of whether they are used inside
,