supabase/realtime

README

Supabase Realtime

Send ephemeral messages, track and synchronize shared state, and listen to Postgres changes all over WebSockets.
Examples · Request Features · Report Bugs

Status

Features	v1	v2	Status
Postgres Changes	✔	✔	GA
Broadcast		✔	GA
Presence		✔	GA

This repository focuses on version 2 but you can still access the previous version's code and Docker image. For the latest Docker images go to https://hub.docker.com/r/supabase/realtime.

The codebase is under heavy development and the documentation is constantly evolving. Give it a try and let us know what you think by creating an issue. Watch releases of this repo to get notified of updates. And give us a star if you like it!

Overview

What is this?

This is a server built with Elixir using the Phoenix Framework that enables 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.

For a more detailed overview head over to Realtime guides.

Does this server guarantee message delivery?

The server does not guarantee that every message will be delivered to your clients so keep that in mind as you're using Realtime.

Quick start

You can check out the Supabase UI Library Realtime components and the repository of the multiplayer.dev demo app.

Developers

Start with DEVELOPERS.md for local setup, mise tasks, and example workflows.

Once your environment is up and running, check out the following docs to customize the server and troubleshooting:

ARCHITECTURE.md - how the cluster, broadcast fan-out and Postgres Changes fit together
ENVS.md - detailed list of all environment variables
ERROR_CODES.md - list of operational codes
OBSERVABILITY_METRICS.md - monitoring information

Postgres compatibility

Versions below refer to supabase/postgres releases unless stated otherwise.

Tenant database	Role	Status	Notes
< 14	-	Not supported	-
14.x	`supabase_admin`	Supported with limitations	Realtime needs a superuser. Only a superuser can set `log_min_messages`, and supautils can't hand it to another role on this version. On Postgres 14.5 and earlier, `realtime.broadcast_changes(...)` fails when a trigger calls it with `PERFORM`.
15.x < 15.14.1.018	`supabase_admin`	Supported	Realtime needs a superuser. `supautils.policy_grants` doesn't cover `realtime.subscription` until supabase/postgres@1b916920.
15.x >= 15.14.1.018, 16.x, 17.x	`supabase_admin`	Supported	Migrations need a superuser. Tenant grants don't. supautils manages the policies.
17.x-orioledb < 17.11.0.004	`supabase_admin`	Supported with limitations	Migrations need a superuser. With `REPLICA IDENTITY FULL`, Postgres Changes UPDATE and DELETE events can miss the old value of large (TOASTed) columns. Broadcast from Database can lose messages sent from a trigger.
17.x-orioledb >= 17.11.0.004	`supabase_admin`	Supported	Migrations need a superuser.
Multigres	`supabase_admin`	Supported	Only Postgres >= 17.x and every commit waits for a standby.

Contributing

See CONTRIBUTING.md

Code of Conduct

See supabase/CODE_OF_CONDUCT.md

License

This repo is licensed under Apache 2.0.

Credits

Phoenix - Realtime server is built with the amazing Elixir framework.
Phoenix Channels JavaScript Client - @supabase/realtime-js client library heavily draws from the Phoenix Channels client library.

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