The VS Code and Open VSX catalogs, September 2026

VSXRank crawls both public registries every night. The numbers below are from the catalog snapshot on 6 September 2026, the first full day after collection started. Nobody else publishes this cut. We will write one of these a month.

The two catalogs, side by side

That is about 110 new Marketplace extensions and 37 new Open VSX extensions a day. Roughly a quarter of Open VSX exists nowhere else.

Do not read the 17k / 115k split as “Open VSX is 15% as large.” Those are listing counts, not users. Cursor, Windsurf, VSCodium, Gitpod and Theia install from Open VSX because the Marketplace licence does not cover them. The interesting number is the overlap: 13,461 extensions already ship to both, and 567 of the last month’s launches did so from day one.

What the first two days of history actually moved

Between two crawls 18 hours apart:

• Marketplace: 84% of extensions did not change at all. The median mover gained a handful of unique installs. Head extensions such as ms-python move by thousands an hour; everyone else is a flat line at daily resolution.
• Open VSX: only 5% were unchanged. Release days produce vertical jumps. Anthropic.claude-code added 131k downloads in a day; another extension jumped 21%. That is not 131k new users. Open VSX downloadCount increments on every version download, including auto-updates. See why Open VSX downloads look inflated.

Intraday resolution therefore means something on Open VSX and almost nothing on the Marketplace. We crawl Open VSX every four hours and the Marketplace once a night. Keyword ranks are a different job; they run after the nightly catalog so the two never overlap.

What this is for

A publisher deciding whether Open VSX is “worth it” usually has one listing and a gut feel. The catalog says:

1. Most of Open VSX is already a twin of a Marketplace listing. If you are not in that 13,461, you are invisible to every editor that cannot talk to Microsoft’s gallery.
2. A quarter of Open VSX has no Marketplace twin. Those 3,968 extensions are not a rounding error, and 312 of them appeared in the last 30 days.
3. Launch velocity on Open VSX is not a trickle. 1,114 extensions published in 30 days is ~6% of the whole registry. The Marketplace’s 3,401 is ~3% of a much larger pile.

We do not rank the two registries against each other in one list. Marketplace unique installs and Open VSX downloads measure different events. Category boards, the landing feed and this report always split them.

What we will measure next month

Once we have 30 days of history, the next report can name movers instead of describing a snapshot: who actually gained unique Marketplace installs, which Open VSX namespaces spiked on a release, and whether dual-registry launches grow faster than Marketplace-only ones. The crawl already stores every row. The limiting factor is calendar, not access.

If you publish, track the listing — yours or a competitor’s. History starts on 5 September 2026 for everyone, including people who sign up later.