Methodology
Sources
- The store's sitemap, read every day, lists every item's ID. New IDs are fetched the same day.
- Each extension's public listing page gives its users, rating, version, permissions and other details.
- Google's update service, asked every day, gives each extension's current version. A new version means the listing is fetched again that day.
How often an extension is checked
- Every week if it has 1,000 or more users, and every month otherwise.
- New extensions again 7 and 30 days after they were published.
- Any extension again as soon as a new version appears.
- Themes and apps once, to learn what they are. They aren't tracked after that.
History starts on 26 September 2026, when tracking began. Charts get a point for every check.
Removed, hidden and missing
- Removed: an extension counts as removed once it's missing from three complete daily sitemaps in a row. Its page stays up with the date and the data as last seen.
- Not visible to our crawler: the store sometimes won't show a listing to our server while still listing it. That isn't counted as removed, and it's checked again every 30 days.
- Not found: the store says it doesn't know the ID. It's checked again every 7 days.
A page that fails to load or can't be read is retried. It never changes an extension's status.
The numbers
- Users and ratings are the store's own figures, as the listing shows them.
- Ranks order live extensions by users. Ties share a rank.
- Growth is the users gained since a count at least 7 or 30 days older.
- Developer pages group extensions by the store's own publisher account ID, so a developer with several accounts appears on several pages.
How the crawler behaves
It runs on one server at a modest rate, obeys the store's robots.txt, stays logged out, and slows down or stops when the store returns errors.
What isn't collected
Full descriptions, screenshots and reviews aren't copied. Developers' contact details are removed before anything is stored. The developer's email is kept only as a keyed hash, which groups a developer's extensions and shows when the email changes, without revealing it.