Tandem

About

Tandem is a sync engine and client-side database for building collaborative apps. Each client gets a local queryable database. Writes apply locally first, sync to a server in the background, and pending changes are replayed on top of server updates. It embeds into an existing frontend and backend instead of requiring a separate hosted service, which makes incremental adoption easier. The README states it is pre-1.0 and APIs change without notice.