triplit

A full-stack, syncing database that runs on both server and client. Pluggable storage (indexeddb, sqlite, durable objects), syncs over websockets, and works with your favorite framework (React, Solid, Vue, Svelte). Maintained by aspen-cloud on GitHub, where it has earned 3,112 stars from the community.

It's actively developed around crdt, database, firestore, and is a solid reference for anyone building with these tools.