Firefox has expanded its Fingerprinting Protection by reporting constant values for several more attributes of user's computers. More Details

Firefox will now also clear the back-forward-cache when receiving the Clear-Site-Data: "cache" response header.

On Linux, Firefox uses less memory and no longer requires a forced restart after an update has been applied by a package manager.

Implemented the closedby attribute and it's related closedBy property on dialogs indicating the types of user actions that can be used to close the associated <dialog> element.

Added support for the URLPattern API, enabling developers to match and parse URLs using a standardized pattern syntax.

Firefox now uses an updated grid sizing algorithm to better align with the CSS Grid specification. Grid layouts that use percentage row sizes or grid items containing elements with aspect ratios (such as images) will now render correctly in more cases.

<input type=color> now recognizes the CSS <color> format in addition to the color hex format (#ffffff). This means that color names like black and more complex strings like rgb(200 200 200) are now valid inputs. For now the value will always be converted to the hex format.

Tapping a persistent notification when Firefox for Android is closed or restarted now properly opens Firefox with the relevant webpage.

Firefox now supports xHE-AAC audio playback on Windows 11 22H2+, macOS, and Android 9+.

When a site asks for camera access, it can now be previewed in the permission dialog. This is especially helpful when switching between multiple cameras.

Unchecking the Group Similar Messages setting now prevents successive similar messages from being grouped so that all messages are displayed in the output.

Starting with Firefox 140, Nightly builds now support TaskSignal: any().

Starting with Firefox 139, Smart Tab Groups is now available in Nightly builds, enhancing the creation of new groups by automating the process of grouping semantically similar tabs and labeling the group.

Starting with Firefox 139, Nightly builds now support the View Transition API.

Improved Drag-and-drop support for blob images.

The Selection.getComposedRanges() API is now available, allowing developers to accurately get selected text ranges across shadow DOM boundaries.

ETP-Strict mode now supports a flexible exception list to fix broken site features caused by tracker blocking. Exceptions are split into baseline (core functionality) and convenience (extra features), letting users choose improved site compatibility without compromising key privacy protections.

On Windows, clicking a persistent notification when Firefox is closed or restarted, will now properly open Firefox with the relevant webpage, instead of just opening the main page of the website.

Improved the scroll speed in the bookmarks dialog to not go beyond the component area.

Firefox now supports the Prioritized Task Scheduling API, enabling developers to assign and manage task priorities.

Starting with Firefox 142, Nightly builds support creating URLs using Text Fragments. You can generate such a URL by selecting a snippet of text on a page and choosing Copy Link to Highlight from the context menu.

Starting with Firefox 140, Nightly builds now support CloseWatcher including integration with popovers and dialogs.

Starting with Firefox 142, Nightly builds now support the Integrity-Policy header allowing websites to ensure that all of their scripts are protected with integrity data. It is currently limited to scripts but will be expanded in the future to provide full web application integrity.

Starting with Firefox 139, Nightly builds no longer dispatch the non-standard afterscriptexecute and beforescriptexecute events.

Starting with Firefox 139, Nightly builds now support PerformanceEventTiming.interactionId, allowing developers to group related input events. This enables support for the Interaction to Next Paint (INP) responsiveness metric.

Starting with Firefox 138, H265 decoding for WebCodecs is now enabled for Nightly Linux builds.

Starting with Firefox 137, H265 decoding for WebCodecs is now enabled for Nightly MacOS builds.

Add-ons can inject resources into web pages, which may serve as fingerprinting vectors for malicious websites. Starting with Firefox 140, in Nightly builds, we are experimenting with an anti-tracking isolation feature for these resources to enhance user privacy.

You can now unload tabs by right-clicking on a tab (or multiple selected tabs) and selecting "Unload Tab". This can be helpful in reducing Firefox's memory and CPU usage.

Added support for the CookieStore API, an asynchronous cookie API for scripts running in HTML documents and service workers.

Added Platform support for aria-keyshortcuts in Linux, MacOS, and Windows.

The Firefox Extensions button can now be removed from the toolbar, giving you more control over how you customize your browser. When the button is hidden, you can access the extensions panel again at any time from the Firefox menu by clicking the Extensions menu item.

Firefox now supports adding custom search engines. To do so, right-click a search field of a supported website and select Add Search Engine, or go to Settings > Search > Add (below the search shortcuts table) to manually enter a search URL.

Firefox will now escape less-than (<) and greater-than (>) symbols when serializing HTML attributes, making certain mXSS attacks on websites more difficult.

Vertical Tabs: You can now keep more — or fewer — pinned tabs in view. Just drag the divider to resize your pinned tabs section.

Firefox now supports the pointerrawupdate event. This event provides lower-latency access to pointer movements by firing as soon as the pointer data is available, typically before the main pointermove event. Unlike pointermove, it performs an additional hit test to determine the target, and fires more frequently, which may impact performance even if only a listener is added. This event is intended for applications that require high-precision input handling and cannot achieve smooth interaction using coalesced pointermove events alone.

On all platforms, Firefox now applies a uniform user agent (UA) style to <h1> elements, regardless of whether they are used inside <article>, <aside>, <nav>, or <section>.

Added support for the Custom Highlight API, which allows to style text ranges.

Firefox for Android now allows includes a "Select All" in Bookmarks.

Added support for requestClose() to HTMLDialogElement.

Added support for the WebAuthn largeBlob extension.

The upload performance of HTTP/3 been significantly improved, particularly on resumed connections (QUIC 0-RTT) and high bandwidth and high delay connections.

The Temporal proposal is now enabled by default in Firefox. Temporal is a better version of Date, for more details, please see https://spidermonkey.dev/blog/2025/04/11/shipping-temporal.html and https://tc39.es/proposal-temporal/docs/.

Full-Page Translations are now available within Firefox extension pages.

Timer throttling for Workers is now supported.

PNG images with transparency now keep their transparency when pasted into Firefox.

Closed <details> elements are now searchable and can be automatically expanded if found via find-in-page.

window.getSelection().toString() now correctly returns the text serialization when text is selected in a text control, improving cross-browser interoperability on some sites.

Starting with Firefox 138, The built-in editor for contenteditable and designMode now handles collapsible white-space before block boundaries and white-space sequences between visible content more consistently with Chrome. As a result, Gecko no longer inserts a padding <br> element after white-space before a block boundary, aligning behavior with other major browsers.

Starting with Firefox 139, Nightly builds now support the hidden=until-found attribute, allowing content to be found via find-in-page when it's otherwise hidden by default.

Starting with Firefox 138, Service Workers are now available in Private Browsing Mode in Nightly builds. This enhancement builds on our efforts to support IndexedDB and the DOM Cache API in Private Browsing through encrypted storage. With this change, more websites, especially those that rely on background tasks, will be able to benefit from Service workers.

Starting with Firefox 136, profile management is now available in Nightly builds. Users can now more easily create and switch between different profiles.

Starting with Firefox 137, you can now you can easily add your signatures to PDFs. Draw, type, or upload your signature, then place it exactly where you want. Save your go-to signatures for next time.

Starting with Firefox 136, scroll-driven animations is enabled in Nightly builds.