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Firefox Nightly — English (US)

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Firefox Nightly — English (US)

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153.0a1 Firefox Nightly

Version 153.0a1, first offered to Nightly channel users on May 19, 2026

Firefox Nightly gets updated every day and as a consequence, the release notes for the Nightly channel are updated continuously to reflect features that have reached sufficient maturity to benefit from community feedback and bug reports.

Warning: Features listed here may or may not make a final release of Firefox.

In addition to these release notes, you can follow ongoing development on our @FirefoxNightly Bluesky account, our @FirefoxNightly Mastodon account as well as read our Nightly Blog.

You can interact with other Firefox Nightly users and give your feedback to Mozilla staff in the Nightly Matrix room on chat.mozilla.org.

Starting with Firefox 152, Nightly builds have an in-memory cache for the JavaScript compilation result, which is shared across navigation within the same domain, in order to improve the page load performance. The cache works in the same way as the existing in-memory cache for the stylesheets and the images. This can affect how the cached requests/responses are handled in DevTools, WebDriver, and WebExtensions APIs such as webRequest and declarativeNetRequest.
Bug 2027803
Starting with Firefox 151, Firefox for Android nightly builds include settings for enabling fine-grained control of AI features and also allows you to block future AI features.
Bug 2029260
Starting with Firefox 152, the address bar in Nightly builds autofills the pages you visit most - including specific pages within a site, not just site homepages - based on your browsing habits, and lets you dismiss suggestions you don’t want.
Bug 2032547
Added support for Apple's system-wide full-screen keyboard command (Globe-F)
Bug 1748950

In Firefox for Android, sharing a remote PDF will now share the file itself, rather than its URL, that you can still share by copying it from the awesomebar.
Bug 2007432

Developer Information
Starting with Firefox 151, the JavaScript Tracer can be enabled from DevTools Settings panel in Nightly builds. This enables tracing all JavaScript function calls. Unlike the performance profiler, this doesn't record a sample; instead, it traces all function calls.
Bug 2022844

Starting with Firefox 152, Nightly builds now support the WebAssembly JS-Promise-Integration proposal, improving the porting of applications to the Web.
Bug 2015877
Starting with Firefox 152, Nightly builds allow the attr() function to be used in any CSS property. It now also allows to specify how the attribute value is parsed into a CSS value.
 Bug 2038939

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Firefox Nightly — English (US)

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See what landed recently in Firefox Nightly!

153.0a1 Firefox Nightly

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