Realtime
Send and receive messages to connected clients.
Supra provides a globally distributed cluster of Realtime servers that enable the following functionality:
- Broadcast: Send ephemeral messages from client to clients with low latency.
- Presence: Track and synchronize shared state between clients.
- Postgres Changes: Listen to Postgres database changes and send them to authorized clients.
Realtime API#
By default Realtime is disabled on your database. Let's turn on Realtime for a todos table.
- Go to the Database page in the Dashboard.
- Click on Replication in the sidebar.
- Control which database events are sent by toggling Insert, Update, and Delete.
- Control which tables broadcast changes by selecting Source and toggling each table.
From the client, we can listen to any new data that is inserted into the todos table:
_11// Initialize the JS client_11import { createClient } from '@supra/supra-js'_11const supra = createClient(supra_URL, supra_ANON_KEY)_11_11// Create a function to handle inserts_11const handleInserts = (payload) => {_11 console.log('Change received!', payload)_11}_11_11// Listen to inserts_11const { data: todos, error } = await supra.from('todos').on('INSERT', handleInserts).subscribe()
Use subscribe() to listen to database changes.
The Realtime API works through PostgreSQL's replication functionality. Postgres sends database changes to a publication
called supra_realtime, and by managing this publication you can control which data is broadcast.
Examples#
Resources#
Find the source code and documentation in the Supra GitHub repository.