Mozilla (addons.mozilla.org)
High Trafficaddons.mozilla.org
Overview
addons.mozilla.org (AMO) is the official Mozilla marketplace for Firefox browser extensions, themes, and plugins. It allows developers to publish and users to discover free add-ons that enhance privacy, productivity, and the visual experience of Firefox. The platform is operated by Mozilla Corporation, the company behind the Firefox web browser.
By the Numbers
Founders
Brendan Eich created the JavaScript programming language in 1995 while at Netscape and later co-founded Mozilla. He also briefly served as CEO of Mozilla Corporation before resigning in 2014.
Eich invented JavaScript in just 10 days in 1995.
Mitchell Baker has been a central figure at Mozilla since its inception, serving in various leadership roles including CEO and Chairwoman. She has been instrumental in guiding Mozilla's mission of internet openness.
Baker was named one of Time magazine's 100 most influential people in the world in 2005.
Funding
Competitors
Google's extension marketplace for Chrome; far larger user base but less focused on privacy-first extensions
Microsoft's marketplace for Edge browser extensions; supports Chromium-compatible extensions
Opera's smaller extension marketplace; fewer extensions and a niche user base
Key People
Appointed interim and then full CEO of Mozilla Corporation in 2024. Previously held leadership roles at Airbnb and PayPal.
Long-serving CTO at Mozilla, focused on Firefox's technical direction and web security standards.
Oversees product strategy for Firefox and related Mozilla products including AMO.
Revenue & Model
Hiring Signals
Tech Stack
Notable Customers
Web Presence
Verified from public records — not AI-estimated.
Trackers & Analytics
Scanned from the HTML addons.mozilla.orgserves — scripts a tag manager injects later won't appear here.
How They're Doing
addons.mozilla.org continues to serve as the primary extension marketplace for Firefox's global user base. Firefox has been losing market share to Chrome over the past decade, but retains a loyal privacy-focused audience. AMO remains highly active with thousands of extensions and millions of monthly users.
●Extensions like YouTube Dislike (917k users) and SponsorBlock (787k users) show strong community engagement
●Mozilla continues to invest in Manifest V3 compatibility discussions and developer tooling for AMO
Prognosis
AMO's future is closely tied to Firefox's ability to maintain and grow its user base in a Chrome-dominated market. Mozilla's strong emphasis on privacy positions AMO well as concerns over Google's Manifest V3 restrictions drive some developers and users toward Firefox. However, declining Firefox market share poses a long-term risk to the platform's relevance.
●Growing privacy concerns may drive users toward Firefox and its extension ecosystem
●Manifest V3 restrictions in Chrome could push extension developers to prioritize Firefox/AMO
●Increased demand for ad-blocking and privacy tools aligns with Firefox's core audience
●Continued decline in Firefox market share reduces the developer and user addressable market
●Google's dominance in the browser market limits AMO's growth ceiling
●Reduced Mozilla headcount (layoffs in 2020 and 2024) may slow platform development
Recent News
Mozilla lays off ~60 employees and restructures product teams
The Verge
Laura Chambers named CEO of Mozilla Corporation, Mitchell Baker steps back
Mozilla Blog
Mozilla releases Firefox 120 with enhanced privacy features and improved extension management
Mozilla Blog
Mozilla announces Firefox's position on Manifest V3, committing to preserve key extension APIs
Mozilla Blog
AMO introduces new recommended extensions badging program to improve user trust
Mozilla Blog
Controversies
Mozilla laid off approximately 250 employees (25% of staff) citing revenue shortfalls exacerbated by COVID-19, drawing significant community concern about Firefox's future.
Co-founder and CEO Brendan Eich resigned after public backlash over a 2008 donation in support of California's Proposition 8 (anti-same-sex marriage ballot measure).
Mozilla announced another round of layoffs affecting ~60 employees, raising concerns about the organization's financial sustainability and Firefox development pace.
Mozilla briefly enabled the Mr. Robot extension silently for all Firefox users as part of a promotional deal, causing user outrage over the lack of transparency and opt-in consent.
Fun Facts
- 01The Mozilla name is a portmanteau of 'Mosaic Killer' — it was originally the internal codename for Netscape Navigator, meant to destroy the Mosaic browser.
- 02addons.mozilla.org has been running in some form since 2004, making it one of the oldest browser extension marketplaces on the internet.
- 03Firefox's iconic logo featuring a fox wrapped around a globe is technically depicting a red panda, not a fox — the animal in the logo is a red panda (also called a 'firefox').
- 04Mozilla earns the vast majority of its revenue from Google paying to be Firefox's default search engine — a relationship worth hundreds of millions of dollars annually despite Google being a direct competitor via Chrome.
Timeline
Laura Chambers becomes CEO; Mozilla undergoes further restructuring and layoffs
Mozilla reaffirms commitment to preserving ad-blocking extension APIs unlike Chrome's Manifest V3 restrictions
Mozilla lays off 250 employees amid revenue pressure
Mozilla controversially silently installs Mr. Robot extension for users, causing backlash
Firefox Quantum (Firefox 57) released with major performance improvements and new WebExtensions API replacing legacy add-ons
Firefox 3 released, setting a Guinness World Record for most software downloads in 24 hours (8 million)
Mozilla Corporation formed as a taxable subsidiary of the Mozilla Foundation
Firefox 1.0 released; addons.mozilla.org launched as the official extension marketplace
Mozilla Foundation established as a non-profit organization
Netscape open-sources its browser code, leading to the creation of the Mozilla project