Tanstack Query doesn't actually store data for you, it just caches what comes back from the queryFn. You would still need to implement your own data store, e.g.

Tanstack Query doesn't actually store data for you, it just caches what comes back from the queryFn. You would still need to implement your own data store, e.g. using IndexedDB or OPFS. And if you wanted both a local data store for offline writes and a network connected backend when available... I'm pretty sure you'd be doing a lot of extra work yourself. That's what a sync engine should give you, I think.