Pointing Vscodium at Open VSX: the extension registry switch that completes the de-Microsofting

Vscodium ships as a telemetry-free build of VS Code, but there's a catch many people miss: the extension gallery it talks to is still Microsoft's Visual Studio Marketplace. So your editor is clean, while your extension traffic — searches, downloads, update checks — still flows through Microsoft's servers. If the point of running Vscodium was to cut that cord, the job is only half done.

The fix is three settings. Vscodium reads extensions.gallery.serviceURL, extensions.gallery.itemURL, and extensions.gallery.controlURL to decide which registry to contact, and you can repoint all of them at the Open VSX Registry, the community-run, vendor-neutral extension catalog hosted by the Eclipse Foundation. This post walks through the change, what you actually gain, and the honest trade-offs.

What the gallery URLs actually control

Every time you open the Extensions view, search for a plugin, or Vscodium checks for extension updates, it makes HTTP requests to the gallery endpoints. The serviceURL handles queries and downloads, itemURL builds the links to extension detail pages, and controlURL is used for gallery metadata. By default all three point at Microsoft infrastructure — even in Vscodium, depending on version and platform, so it's worth checking rather than assuming.

Open VSX is the alternative: an open-source registry where publishers explicitly push their extensions, built from public source, with no telemetry baked into the distribution pipeline. It's the same registry that projects like Gitpod and Eclipse Theia rely on.

Making the switch

Open the Settings JSON editor in Vscodium (Ctrl+Shift+P → "Preferences: Open User Settings (JSON)") and add:

{
  "extensions.gallery.serviceURL": "https://open-vsx.org/vscode/gallery",
  "extensions.gallery.itemURL": "https://open-vsx.org/vscode/item",
  "extensions.gallery.controlURL": "https://open-vsx.org/vscode"
}

Save the file, then reload the window (Ctrl+Shift+P → "Developer: Reload Window"). No restart of the whole application is strictly required, and no account or login is involved — Open VSX is anonymous for consumers.

This changes only which server your editor queries; it doesn't touch installed extensions, so there's nothing to roll back beyond deleting the three lines if you change your mind.

How to confirm it worked

Don't just trust the settings file. Two quick checks:

1. Open the Extensions view and search for an extension known to exist on Open VSX, such as esbenp.prettier-vscode (Prettier). If it appears and installs, the registry switch is live.
2. For stronger evidence, open View → Output, pick the Extension Host or Shared channel, and trigger a search. You should see requests going to open-vsx.org rather than marketplace.visualstudio.com.

If searches return nothing at all, double-check the URLs for typos — a malformed serviceURL fails quietly and just looks like an empty catalog.

The trade-off: a smaller, sometimes slower catalog

Here's the part to weigh before committing. Open VSX only contains extensions whose publishers explicitly pushed them there. That has real consequences:

• Microsoft's own extensions are absent or unofficial. The flagship Python, C/C++, and C# extensions are published to the Microsoft Marketplace under a license that restricts use to official VS Code builds. Community-maintained alternatives exist on Open VSX (for example, ms-python.python may appear via unofficial republishing, and tools like clangd or basedpyright cover similar ground), but they aren't the same artifacts.
• Update latency varies. Popular community extensions like Prettier or ESLint are usually current, but less-maintained ones can lag their Marketplace versions, meaning delayed bug fixes.
• Some extensions assume Microsoft services. Anything that phones home to Azure-backed APIs or bundles licensed binaries may misbehave regardless of where you install it from.

A sensible approach: switch the registry, then audit your critical extensions in a throwaway workspace before relying on them for real work. Most language-agnostic tooling — formatters, linters, Git helpers, themes — is fully present and identical in behavior.

Why it's worth the three lines

Running Vscodium with the default gallery is like installing a privacy-hardened browser and leaving the default search engine phoning home. Repointing the gallery to Open VSX aligns the extension supply chain with the reason you chose Vscodium in the first place: open source end to end, no telemetry, no Microsoft account dependency. The cost is a smaller catalog and occasional version lag — a fair trade for most workflows, and one you can evaluate extension by extension. Make the change, verify with a Prettier search, and check your must-have tools before your next real project.