An AI-powered Firefox extension designed to intelligently summarize various forms of digital content including emails, articles, and videos. Orbit leveraged the Mistral 7B language model, hosted on Mozilla’s Google Cloud infrastructure, to process and condense information for users. Despite its innovative approach to content consumption, Mozilla announced the service’s termination on June 8th, 2025, with complete functionality cessation scheduled for June 26th, 2025.

A popular read-it-later service that enabled users to save, organize, and share web content across devices. Originally an independent platform, Pocket formed a strategic partnership with Mozilla in 2015 before being fully acquired in 2017. While Mozilla initially promised to open-source the platform’s backend infrastructure, this commitment remained unfulfilled. The service will cease operations on July 8th, 2025, as Mozilla redirects resources toward core Firefox development.

A consumer protection platform that specialized in detecting fraudulent and manipulated product reviews across major e-commerce sites like Amazon and Walmart. Following Mozilla’s acquisition in 2023, Fakespot’s technology was integrated into Firefox’s ecosystem through Firefox Suggest and the Review Checker feature. The standalone service will shut down on July 1st, 2025, with Mozilla citing financial unsustainability as the primary reason.

A community-focused text sharing platform built on the dpaste framework and maintained by Mozilla. The service allowed developers and community members to share code snippets, documentation, and text in various formats including Markdown and reStructuredText. Due to declining user engagement and maintenance costs, Mozilla announced its closure in February 2025, with final shutdown occurring on March 31st, 2025.

Mozilla’s venture into decentralized social networking through a dedicated Mastodon instance. Initially announced in late 2022 as part of Mozilla’s broader vision for healthier online communities, the platform launched in private beta during May 2023. However, the experiment was short-lived, with closure announced in September 2024 without detailed explanation, leading to service termination on December 17th, 2024.

A comprehensive password management solution that seamlessly integrated with Firefox’s desktop browser while offering dedicated mobile applications for iOS and Android platforms. As Mozilla enhanced Firefox’s native password management capabilities across all platforms, the standalone Lockwise applications became redundant. The dedicated mobile apps were phased out in late 2021, consolidating password management functionality within the main Firefox mobile browsers.

Mozilla’s Internet Relay Chat network (irc.mozilla.org) served as a primary communication hub for the organization’s global community. In 2019, Mozilla identified persistent challenges with abuse, harassment, and technical limitations that compromised the platform’s effectiveness. After evaluating alternatives, Matrix was selected as the successor for real-time communication. The IRC infrastructure was permanently decommissioned on March 2nd, 2020.

A privacy-focused file sharing platform that utilized end-to-end encryption to protect user data during transmission. Despite its innovative security features and positive user reception, the service became a target for malicious actors who exploited it for distributing harmful content. Following a temporary suspension in July 2020 due to widespread abuse, Mozilla made the difficult decision to permanently discontinue the service in September 2020.

A cross-platform note-taking solution that provided encrypted synchronization between a Firefox browser extension and an Android mobile application. The service emphasized user privacy by implementing client-side encryption for all stored content. Mozilla announced the discontinuation in November 2020, providing users with export functionality to preserve their encrypted notes before service termination.

An educational browser extension that democratized web development by allowing users to inspect, modify, and share webpage source code without technical expertise. Part of Mozilla’s broader educational initiative, X-Ray Goggles made web technologies accessible to learners of all backgrounds. The project was officially retired in December 2019 as Mozilla shifted focus to other educational tools and platforms.

An intuitive web-based coding environment designed to teach web development fundamentals through hands-on creation and immediate publishing capabilities. Thimble simplified the web development process, enabling students and educators to build and deploy websites without complex setup procedures. When Mozilla ceased support in December 2019, users were offered migration paths to Glitch, ensuring continuity for ongoing educational projects.

Originally launched as “Collusion,” this Firefox extension provided users with unprecedented visibility into online tracking mechanisms by visualizing cookie-based surveillance networks. The tool created interactive graphs showing how tracking cookies followed users across different websites, revealing the interconnected nature of digital advertising ecosystems. While Firefox’s Enhanced Tracking Protection eventually superseded Lightbeam in 2019, the newer feature unfortunately lacks the compelling data visualization that made Lightbeam so educational.

An experimental runtime that reimagined Node.js by replacing Google’s V8 JavaScript engine with Mozilla’s SpiderMonkey engine. This ambitious project aimed to diversify the JavaScript runtime ecosystem while supporting Mozilla’s Positron desktop application framework. SpiderNode represented Mozilla’s effort to provide developers with alternatives to Chromium-based technologies in the rapidly evolving JavaScript landscape.

Mozilla’s ambitious attempt to create an Electron alternative using Firefox’s Gecko rendering engine and SpiderMonkey JavaScript engine, coupled with the SpiderNode runtime. Positron promised Electron compatibility while offering developers a choice beyond Chromium-based solutions for desktop application development. Despite its technical innovation and strategic importance, the project was discontinued in 2017 as Mozilla prioritized other initiatives.

A revolutionary identity verification system that envisioned a decentralized, privacy-respecting approach to web authentication. Persona eliminated the need for multiple account passwords by providing a universal, cross-browser single sign-on solution. Despite its technical elegance and privacy advantages, the system struggled with adoption challenges in a market dominated by centralized identity providers, leading to its discontinuation in 2016.

Mozilla’s bold venture into mobile operating systems, built entirely on web technologies using the Gecko rendering engine and Linux kernel. Firefox OS aimed to democratize mobile computing by making smartphones more affordable and developer-friendly through HTML5-based applications. While the operating system showed promise and gained partnerships with device manufacturers, commercial smartphone sales ended in 2015, with complete development cessation in 2016 due to market challenges.

An innovative Flash Player replacement built entirely with web-standard technologies, using HTML5 and JavaScript to interpret and execute Adobe Flash content. Shumway featured a custom ActionScript interpreter written in JavaScript, eliminating the need for proprietary plugins. As Flash usage declined across the web and browsers moved toward plugin-free architectures, Shumway’s relevance diminished, contributing to its eventual discontinuation.

A pioneering WebRTC-powered video communication service embedded directly within Firefox (versions 34-49). Hello revolutionized video calling by eliminating account requirements—users could initiate conversations simply by sharing a URL. While optimized for Firefox, the service maintained compatibility with other WebRTC-enabled browsers, demonstrating Mozilla’s commitment to open web standards for real-time communication.

A groundbreaking web development tool that transformed traditional 2D web page inspection into an immersive 3D experience. Beginning as a community extension before integration into Firefox’s developer toolkit, Tilt allowed developers to visualize HTML element nesting through spatial depth, with interactive pan, zoom, and rotation controls. This innovative visualization approach can be observed in Mozilla’s developer tools demonstration videos.

A visual mobile application development platform that empowered non-programmers to create functional apps using drag-and-drop blocks and signal-based logic systems. As part of Mozilla’s educational technology suite, Appmaker democratized app development by removing traditional coding barriers. The platform was retired alongside Popcorn Maker in September 2015 to concentrate resources on the broader Webmaker initiative.

A powerful application development framework that enabled developers to create sophisticated desktop applications using Mozilla’s Gecko engine and XUL (XML User Interface Language). Beyond powering Firefox and Thunderbird, XULRunner supported numerous third-party applications including Flickr Uploadr, Google AdWords Editor, IBM Lotus Notes, and many others, demonstrating its versatility and enterprise appeal.

A Mac-exclusive web browser that combined Firefox’s powerful Gecko rendering engine with a meticulously crafted native macOS interface. Unlike Firefox’s cross-platform XUL framework, Camino embraced Apple’s design principles and system integration standards, delivering a browsing experience tailored specifically for Mac users. Development officially concluded in 2013 as the project’s volunteer community shifted focus to other initiatives.

An experimental interface paradigm that introduced natural language command processing to web browsing, enabling users to execute complex web-based tasks through conversational input. Ubiquity’s extensible architecture allowed any website to provide specialized commands that users could selectively enable, creating a personalized and efficient browsing workflow that anticipated many concepts later seen in modern voice assistants.

Firefox’s pioneering JavaScript debugging environment that provided developers with comprehensive code analysis and troubleshooting capabilities. As development momentum slowed by 2011, Venkman was eventually superseded by the more advanced Firebug extension. The comprehensive Venkman walkthrough documentation showcases the breadth of its debugging capabilities.

An ambitious distributed messaging platform designed for secure, decentralized communication in both individual and group contexts. Deuxdrop evolved from Mozilla’s earlier Raindrop project, incorporating lessons learned from the previous iteration while advancing Mozilla’s vision of user-controlled, privacy-focused communication infrastructure.

A site-specific browser solution that transformed web applications into desktop-native experiences, predating similar concepts by several years. Prism leveraged Firefox’s engine while adding desktop integration features like offline storage, hardware acceleration, and system notifications. Available as both standalone software and a Firefox extension, Prism pioneered the concept of Progressive Web Apps long before the term became mainstream.

A dedicated cross-platform calendar application that provided comprehensive scheduling and event management capabilities independent of email clients. Sunbird shared its core codebase with the Lightning extension, which integrated identical functionality directly into Mozilla Thunderbird. Development resources were consolidated around Lightning in 2010, leading to Sunbird’s retirement in favor of the integrated solution.

Mozilla’s early mobile web browser optimized for resource-constrained devices including smartphones, PDAs, and handheld computers. Supporting platforms like Windows Mobile, Windows CE, and GPE, Minimo pioneered mobile web browsing before smartphones became ubiquitous. The project evolved into Firefox Mobile (codenamed Fennec), adapting to the emerging smartphone ecosystem.

A short-lived browser engine project focused on enhancing Netscape Communicator’s performance and reliability through architectural improvements. Open-sourced in March 1998 as part of Netscape’s broader open-source strategy, Mariner was quickly abandoned by October of the same year when Netscape pivoted to developing the revolutionary NGLayout engine, which later became the foundation for Mozilla’s Gecko.

A high-performance Java Virtual Machine featuring just-in-time compilation technology that was originally developed as a commercial product by Netscape. Following Netscape’s strategic shift away from Java development, ElectricalFire was released as open-source software in 1999, contributing to the broader ecosystem of alternative JVM implementations and performance optimization research.

A Java-based email and newsgroup client built on Sun Microsystems’ JavaMail API framework. Grendel originated from Netscape’s ambitious “Project Xena”—a complete Java reimplementation of Netscape Navigator. When open-sourced in 1999, Grendel represented one of the more complete components extracted from this larger, ultimately abandoned rewrite effort.

Mozilla’s customized implementation of the LXR source code indexing system, designed to enhance developer comprehension of Mozilla’s extensive codebase through advanced cross-referencing and navigation capabilities. As Mozilla’s development needs evolved, work began on DXR (Developer eXperience Re-imagined), a next-generation code analysis platform featuring superior static analysis and user interface design. MXR was retired once DXR achieved production readiness.

An ambitious but ultimately unrealized visual development environment for Mozilla’s XUL user interface framework. Vixen was envisioned to provide drag-and-drop interface design capabilities similar to popular RAD (Rapid Application Development) tools like Borland Delphi and Microsoft Visual Basic, potentially democratizing XUL application development. Unfortunately, the project appears to have stalled in early development phases and never achieved its intended functionality.