Has anyone tried setting up Mozilla Sync with a self-hosted Sync Storage server?

[antonionardella]

Hi everyone 👋

I'm would like to experiment with self-hosting the Mozilla Sync infrastructure and integrating it with Zen Browser. I wanted to ask if anyone here has already tried setting up Mozilla Sync using the official syncstorage-rs server.

I'm following Mozilla's guide on running Firefox Accounts and with a custom Sync server, and I’m specifically interested in:

• Whether Zen Browser supports or can be configured to use a custom Sync server. Looking at about:config it should work
• Any success stories or blockers you encountered setting up and using syncstorage-rs with Zen.
• If any additional code tweaks or flags were needed in Zen to get Sync working.

Would love to hear about your experience or get any pointers from folks who’ve tried this.

Thanks in advance!
Antonio

[dosubot[bot]]

Hi @antonionardella! I'm Dosu and I’m helping the desktop team.

Zen Browser supports configuring a custom Mozilla Sync server via about:config, just like Firefox. You can set prefs like services.sync.serverURL and identity.fxaccounts.serverURI to point to your self-hosted syncstorage-rs instance—there are no hardcoded restrictions or Zen-specific tweaks required for this to work. The sync engine and endpoint logic are inherited from upstream Firefox, so the process and requirements are the same as described in Mozilla's official guides¹.

There aren't any documented success stories or blockers specifically about using syncstorage-rs with Zen, but the technical foundation is compatible. The only Zen-specific sync change is the addition of "workspaces" as a syncable data type, which doesn't affect endpoint configuration². General sync issues (like disconnects or profile bugs) have been reported, but these are not related to custom server setups and were resolved by creating a new profile³.

One thing to note: syncing between Firefox and Zen Browser can cause loss of settings or break features, since Firefox doesn't support Zen-specific data⁴.

To reply, just mention @dosu.

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Footnotes

1. Zen Browser sync engine is based on Mozilla's upstream Sync system and supports endpoint configuration via about:config ↩

2. Zen-specific sync changes only add "workspaces" as a new engine; endpoint selection is unchanged ↩

3. General sync issues resolved by creating a new profile ↩

4. Syncing between Firefox and Zen can cause loss of settings and functionality ↩