Browser engineering, standards, performance, and the open web.
It isn’t often that new image formats land in browsers. In the early 2000s we had JPEG, GIF, and PNG. The 2010s gave us WebP, which was a modest step up from JPEG. But the 2020s have given us two new image formats that are a big step up from previous formats: …
This is the technical companion to our update on Distilled, “Keeping the web open and private in the bot era.” Here we take a deeper look at the problem space, the design we’re proposing, and the problems still left to solve. Bots (and privacy-preserving brows…
Support for Web Serial in Firefox 151 for Desktop Firefox can now connect directly to microcontrollers, development boards, 3D printers, power meters, and other serial-connected hardware from the web. Starting in Firefox 151 for Desktop, support for the Web Se…
Two weeks ago we announced that we had identified and fixed an unprecedented number of latent security bugs in Firefox with the help of Claude Mythos Preview and other AI models. In this post, we’ll go into more detail about how we approached this work, what w…
The open web is a critical platform for applications that handle highly sensitive data, from private communications to financial transactions and medical records. Traditionally, servers are trusted to deliver the appropriate code and resources for their web ap…
In January, we introduced our Nightly package for RPM-based Linux distributions. Today, we are thrilled to announce it is now available for Firefox Beta! Firefox Beta is great for testing your sites in a version of Firefox that will reach regular users in the …
This post is an expanded version of a presentation I gave at the 2025 WebAssembly CG meeting in Munich. WebAssembly has come a long way since its first release in 2017. The first version of WebAssembly was already a great fit for low-level languages like C and…
Cross-site scripting (XSS) remains one of the most prevalent vulnerabilities on the web. The new standardized Sanitizer API provides a straightforward way for web developers to sanitize untrusted HTML before inserting it into the DOM. Firefox 148 is the first …
The Interop Project is a cross-browser initiative to improve web compatibility in areas that offer the most benefit to both users and developers. The group, including Apple, Google, Igalia, Microsoft, and Mozilla, takes proposals of features that are well defi…
Firefox is now the first and the only browser to deploy fast and comprehensive certificate revocation checking that does not reveal your browsing activity to anyone (not even to Mozilla). Tens of millions of TLS server certificates are issued each day to secur…
Beginning in version 138, Firefox will offer an alternative to DLL injection for Data Loss Prevention (DLP) deployments in enterprise environments. DLL Injection DLL injection into Firefox is a topic we’ve covered on the Hacks blog before. In 2023, we blogged …
Interop 2025 continues the mission to make the web more consistent across browsers, building on 2024’s 95% interoperability score. This year, 19 focus areas target key developer needs and long-standing issues, including WebRTC improvements, Storage Access API,…