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Chrome vs Firefox vs Edge extension stores: 362,889 listings compared

Chrome vs Firefox vs Edge extension stores, judged by 362,889 listings in our August 2026 catalog snapshot: upkeep, MV3, users, ratings. Which earns trust?

Maxim Kosterin
10 min read
Three hairline puzzle-piece outlines standing in a row on a thin ground line, each holding an orange watercolor wash at a different level: nearly full, about half, and a shallow pool at the base.
Three hairline puzzle-piece outlines standing in a row on a thin ground line, each holding an orange watercolor wash at a different level: nearly full, about half, and a shallow pool at the base.

People ask me which browser has the "safest" extension store, as if the store logo were a health rating. It isn't. But the extension stores really are different products: different rules, different developer economics, different levels of neglect. And our own catalog, which tracks hundreds of thousands of listings across all three, is a decent way to measure that.

So here's data instead of vibes. I pulled the August 24, 2026 snapshot of the Extenshi catalog: 362,889 live listings. That's 242,166 on the Chrome Web Store, 98,450 on Firefox Add-ons (AMO) and 22,273 on Edge Add-ons.

One note first: this compares the stores as ecosystems. It can't tell you whether any single extension is safe, and malicious listings show up on all three.

Quick verdict

All numbers are from our August 24, 2026 catalog snapshot.

Chrome Web Store: the healthiest shelf. 66% of listings had an update in the past year, and no available listing was still on Manifest V2. Stricter data rules have been enforced since August 1, 2026. The catch: the top 1% of listings hold 92% of users.

Firefox Add-ons: the most structured disclosure and the most engaged users. The median listing gets one rating per 10 users, three times Chrome's median. But 53.5% of listings had gone a year without an update, and 64% still run Manifest V2, which Mozilla keeps supporting.

Edge Add-ons: the smallest and stalest shelf. 64.9% of listings had gone a year without an update, and the median listing gets one rating per ~132 users. Microsoft's MV3 timeline (revised September 15, 2026) still says "TBD" for when it stops accepting MV2 updates.

Bottom line: Chrome wins on maintenance, Firefox on transparency and community, Edge on nothing here. And no store's health makes an individual extension safe.

The scoreboard

A listing counts as live when its latest snapshot isn't flagged unavailable. Percentages are over listings where the field is known, and coverage is near-total.

Chrome Firefox Edge
Live listings 242,166 98,450 22,273
No update in 12+ months 82,054 (33.9%) 52,711 (53.5%) 14,458 (64.9%)
No update in 24+ months 38,096 33,537 11,382
Manifest V3 100.0% 35.6% 87.4%
Store-reported users, summed 1.90B 98M 1.37B
Top 1% share of users 92.0% 91.0% 95.9%
Median ratings per user ~0.033 ~0.10 ~0.008

Maintenance: who's still showing up

Nearly 150,000 listings, about 4 in 10, hadn't shipped an update in over a year. That's a third of Chrome's shelf, versus 53.5% of Firefox's and 64.9% of Edge's. Over half of Edge's catalog hadn't been touched in two years.

Stale means no patches when a browser API bug drops and no fixes when store policies change. It also means nobody notices if the listing changes hands, which is how the ownership-transfer attacks I covered earlier this year started. More in abandoned browser extensions: how to check yours.

It isn't really getting better. The June 22 snapshot had stale shares of 35.9% Chrome, 54.5% Firefox and 67.3% Edge. Since then the shares dipped, but the raw stale count rose in every store. Our Chrome catalog grew about 15% in that window, so new listings diluted the share; old extensions didn't start shipping updates.

Platform migration: three extension stores, three timelines

This is the sharpest difference, and on Chrome the story is over. Our August 24 snapshot had no available Chrome listing still on MV2. On August 31, 2026, Google removed all remaining MV2 extensions from the Web Store, per its MV2 timeline. Why that didn't strand the ad blockers is in my Chrome MV2 removal breakdown.

Edge was 87.4% MV3, with 2,807 MV2 listings still live. Microsoft's migration timeline, revised September 15, 2026, now dates the warnings: in Partner Center since August 2026, and for some users from mid-September. It expects deprecation for enterprise customers to begin in early 2027.

But there's still no deadline. When Partner Center stops accepting MV2 updates is "TBD", and the page gives no date for MV2 to stop running for everyone else. Edge publishers are planning around warnings, not a cutoff.

Firefox is the deliberate outlier: 63,273 live MV2 listings, nearly two-thirds of the catalog. Mozilla said in March 2024 it has "no plans to deprecate MV2" and repeated in February 2025 that it's keeping MV2 alongside MV3. That makes Firefox the refuge for extension types Chrome squeezed out. It's also the store where over half the listings had gone a year without an update.

Disclosure rules: who makes developers show their work

All three stores demand privacy paperwork, with different teeth.

Chrome's policy update, enforced since August 1, 2026, says collected user data must be "strictly necessary" to the extension's disclosed single purpose. Developers must also proactively tell users when their data handling changes. I covered what that means in the Chrome Web Store policy update piece.

Firefox went another way. Since November 3, 2025, every new add-on must declare in its manifest whether, and what, personal data it collects. Firefox shows that in the install prompt and on the AMO listing. Older add-ons don't have to yet; Mozilla's docs say they will later.

Separately, Firefox 153 made local-file access its own permission, off by default even for installed extensions, per Mozilla.

Edge's developer policies require consent before collecting sensitive information, plus a privacy policy that states how user data is handled. My ranking: Firefox first, for putting the declaration in the manifest. Chrome second, for the rules it now enforces. Edge third, because disclosure lives in the developer's privacy policy.

Users and attention: the head eats everything

Every store is a hit economy, but Edge is the extreme. Its 21,251 listings with a user count report 1.37B users combined. That's about 64,500 per listing on average, versus ~8,200 on Chrome and ~1,300 on Firefox. The top 1% hold 95.9% of that, so about 210 listings carry nearly the whole store.

A caveat: each store counts users its own way, and one person with five extensions counts five times. Read these totals as counters, not market share.

Firefox shows the tail from the other side. AMO is the only one of the three that publishes weekly downloads, and the median Firefox add-on got one download per week. The p90 was ten; the top listing pulled 224,585. On AMO you're publishing for a small, specific audience, not Chrome's crowd.

That audience rates what it uses. Take each listing's ratings divided by its users, and the median is ~0.10 on Firefox, ~0.033 on Chrome and ~0.008 on Edge. The median Firefox listing gets about 13 times as many ratings per user as the median Edge one. That's why I read AMO reviews first when vetting a small extension.

Publishing is fragmented too. Of 205,522 distinct publisher names, 77% have exactly one listing (names are free text, so this is approximate).

What the store data can't tell you

Two things, and they're the important ones.

Malware doesn't respect store boundaries. Sleeper extensions behave normally, sometimes for years, until a malicious update. Malwarebytes documented one campaign, GhostPoster, that started on Edge and spread to Chrome and Firefox; I covered it in sleeper extensions go cross-browser. A healthier store lowers the average risk, not the risk of the listing you're about to install.

The browser underneath matters too. A privacy consultant's critique, reported by The Register, found Chrome ships almost no built-in anti-fingerprinting defenses. Firefox has a resistFingerprinting setting, and Brave randomizes ("farbles") what sites can read. More in Chrome's fingerprinting gap.

Your risk is the store times the browser times the listing, and only the last is fully in your control.

FAQ

Which browser store is safest for extensions? On ecosystem health, Chrome: the best maintenance rate, a finished MV3 migration and active policy enforcement. But safety is per extension, and all three stores have hosted malicious listings.

Are Firefox extensions safer because Firefox is more private? Not automatically. New add-ons must declare data collection, and listings get more ratings per user. But in our August 2026 snapshot, over half of AMO was stale and nearly two-thirds was MV2.

Should I install extensions from Edge Add-ons? Edge can also install from the Chrome Web Store. When an extension is on both, compare the two listings' last-updated dates and ratings. On Edge Add-ons, check the update date first: 64.9% of listings had gone a year without one (August 2026 snapshot).

Final recommendation

  • Default shelf: Chrome Web Store, for the best-maintained catalog and newly tightened data rules.
  • For disclosure nerds and small tools: Firefox Add-ons, for in-manifest data declarations and users who leave ratings.
  • On Edge: install deliberately, and check the last-update date first.
  • Everywhere: judge the listing, not the logo. Paste its store URL into the checker to see its safety score and permissions.

Check an extension →

For extensions you already run, npx @extenshi/guard scan checks the ones you installed from a store against the catalog and flags those worth a second look (free account needed).

Scan the extensions you installed from a store with Guard →

Sources

Methodology

Catalog numbers come from the Extenshi catalog database (extensions_catalog), queried read-only by autogen/db-insights/generate.py (run 2026-08-24; trend against the 2026-06-22 run). Each metric counts live listings (latest snapshot not flagged unavailable) with a known value:

  • Abandonment: lastUpdated older than 12 or 24 months at the run date.
  • Users: store-reported usersNumeric, summed per store. Stores count differently and one person counts once per extension, so totals aren't comparable across stores. Weekly downloads are AMO's weeklyDownloads (Firefox-only).
  • Ratings per user: the median of ratingCount divided by usersNumeric, over listings with both (Chrome 111,309; Firefox 28,101; Edge 10,217).
  • Publishers: authorName is free text, so counts are approximate.

This article is based on publicly available store data, official browser-vendor documentation and security research, plus first-party Extenshi catalog aggregates. Extenshi does not independently verify all claims made by third-party researchers. References to specific companies or products reflect the findings of cited sources and do not constitute accusations of intentional wrongdoing. If you believe any information is inaccurate, please contact us at [email protected].

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