I have a WebGL app and since Firebase does not have plugin for Unity WebGL I am using REST and the basic GET call looks like this ( using Unity RestClient )
RestClient.Get($"https://rtdb.firebaseio.com/Users/{localUser_dbId}/partyID/.json").Then(response => { })
How can I implement listening to value changes in the database? Something like new message was added to chat etc.
To get realtime updates through the REST API, you'll have to implement its REST streaming protocol which is based on EventSource / Server-Sent Events.
To start this protocol, set the request's Accept header to text/event-stream, which tells the server you want to receive SSE events instead of a regular REST response.
You'll then get all updates over a single connection/request, and send all write operations over separate connection.