How does history sync works between for example emby and jellyfin with multiple users

[overload73]

Is there some sort of user mapping magic happening behind the scenes? I enable history syncing between Emby and Jellyfin but was wondering how the user mapping is done. Or if CW can be used in a multi user env.
Thanks

[cenodude]

Well, it doesnt. you can configure on user per instance/container as there is no multi user env.
It does have multi layered whitelisting per server and per pair.. but no specific user mapping.

So either use multiple containers... or perhaps its beter, in your specific usecase, to look at another project that is more inteded for media server vs media server sync and has multi user support. It's called watchstate

[DevDema]

Sorry, but I don't believe you answered his first question.

How does this project map the users between services, if the same person has two completely different account between Jellyfin and Plex? How do you unify the two accounts' data?

[cenodude]

Let me explain it differently: there’s no user mapping here, and it doesn’t care about “users” as an entity.

For syncing, it only cares about API access to read items. So if you authenticate as user X, it will read the items for user X. That’s why it lives under authentication providers: it manages authentication so we can access the data (ratings, history, watchlist).

• So yes, you can read items for user X on Jellyfin and sync them to user Y on Plex/Emby/whatever. That’s fine as long as user Y’s library resolves the same external IDs (movies/shows). If not, you’ll end up with unresolved items.
• Or: you can import data from user X on Jellyfin, edit it in the CW Editor (block items, add items, whatever), and only then sync that dataset to another server or tracker, to any user you want.

The only downside is that CW does not support multiple users per server or tracker. It’s one user per provider (Plex, Jellyfin, etc.), regardless of who that user is. They can be the same person everywhere, or completely different users per service. You can switch which user is linked in the auth providers, but keeping track of that will be an absolute chore. And i will not provide any support on that.

No user accounts are involved in that workflow beyond API access to read/write the data. There is also no user account involved/stored in the state file. It just doesnt know, nor does it care.

One small nuance for completeness: the Plex Watchlist isn’t stored on your Plex server, it lives in Plex’s cloud Discovery services. But it’s still just API access, and the same Plex token/API access is used for both Plex servers and Plex cloud services.