Skip to content
MH

Mozilla Hacks

The web developer blog from Mozilla.

20 articles0 followers#Web Development
MHMozilla Hacks

Intent to Ship: JPEG XL

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: AVIF and JPEG […] The post Intent to Ship: JPEG XL…

Web Development3 min read
MHMozilla Hacks

PACT: Anonymous Credentials for the Web

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 browsers) not welcome Browse a news site in a private window.…

AI & ML17 min read
MHMozilla Hacks

Announcing Web Serial Support in Firefox

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 Serial API allows web applications to communicate with…

Web Development5 min read
MHMozilla Hacks

Behind the Scenes Hardening Firefox with Claude Mythos Preview

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 we found, and advice for other projects on making […] The…

AI & ML11 min read
MHMozilla Hacks

Trustworthy JavaScript for the Open Web

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 applications to browsers, who then provide a secure and…

Web Development3 min read
MHMozilla Hacks

Why is WebAssembly a second-class language on the web?

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 C++, and immediately enabled many new kinds of […] The…

Web Development12 min read
MHMozilla Hacks

Launching Interop 2026

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 defined in a sufficiently stable web standard, and have good…

Web Development7 min read
MHMozilla Hacks

Launching Interop 2025

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, and CSS Zoom. The post Launching Interop 2025 appeared…

Web Development8 min read
MHMozilla Hacks

Llamafile v0.8.14: a new UI, performance gains, and more

Discover the latest release of Llamafile 0.8.14, an open source AI tool by Mozilla Builders. With a new command line chat interface, enhanced performance, and support for powerful models, Llamafile makes it easy to run large language models (LLMs) on your own hardware. Learn more about the updates and how to get…

AI & ML4 min read
MHMozilla Hacks

Announcing Official Puppeteer Support for Firefox

We’re pleased to announce that, as of version 23, the Puppeteer browser automation library now has first class support for Firefox. This means that it’s now easy to write automation and perform end to end testing using Puppeteer, and run against both Chrome and Firefox. The post Announcing Official Puppeteer Support…

Web Development8 min read
MHMozilla Hacks

Snapshots for IPC Fuzzing

Process separation remains one of the most important parts of the Firefox security model and securing our IPC (Inter Process Communication) interfaces is crucial to keep privileges in the different processes separated. We take a more detailed look at our newest tool for finding vulnerabilities in these interfaces –…

AI & ML3 min read
MHMozilla Hacks

Experimenting with local alt text generation in Firefox Nightly

Firefox 130 will introduce an experimental new capability to automatically generate alt text for images using a fully private on device AI model. The feature will be available as part of Firefox’s built in PDF editor, and our end goal is to make it available in general browsing for users with screen readers. The post…

AI & ML9 min read
MHMozilla Hacks

Llamafile’s progress, four months in

When Mozilla’s Innovation group first launched the llamafile project late last year, we were thrilled by the immediate positive response from open source AI developers. It’s become one of Mozilla’s top three most favorited repositories on GitHub, attracting a number of contributors, some excellent PRs, and a growing…

AI & ML7 min read
You're all caught up ✓