From the results of a query, to a single field of a document, with RxDB you can observe everything. This enables you to build realtime applications fast and reliable. It does not matter if the data was changed by a user event, another browser tab or by the replication. Whenever your data changes, your UI reflects the new state. You can either use RxJS or add custom reactiveness libraries like signals or other state management.
RxDB supports replication with a CouchDB server or any custom GraphQL endpoint which smoothly integrates with your existing infrastructure. Also you can use the replication primitives plugin to create custom replications over any protocol like HTTP, Websocket, WebRTC or Firestore.
RxDB follows the Offline First paradigm where an application must work as well offline as it does online. This is done by persisting data locally on the client side and replicating it in the background. RxDB can even be used solely on the client side, with no backend at all.
Book a one hour consulting session with the RxDB maintainer. I will answer all your questions, give proposals for your use case and we can even do a pair programming session if you have a specific problem in your source code. You can book this by doing a one-time donation via github sponsors.