[roncesvalles]

Offline-first databases are a hard problem because there isn't just one copy of the database on the user's side, there are N copies - every browser tab or device on which the user can open the local database and make an edit. It's basically an AP multi-master database (= the same row can be edited at different nodes at the same time), and you likely cannot achieve good results without a database that natively supports multi-master operations.

[9dev]

That’s not necessarily true; if you use Origin Private Filesystem along with a Web Worker that acts as a local database server and works off a single SQLite database, you at least have a single DB file per device. From there on, your problem becomes state reconciliation on the server, which CRDTs should help solving.

Not an easy problem for sure, but the web platform is surprisingly capable these days.

[roncesvalles]

CRDTs are so-so and likely cause issues with maintaining relational DBs' transactional consistency. There's a reason none of the NewSQL databases (to my knowledge) are multi-leader.