Docs

Realtime subscriptions

That it must be turned on per table, and that access rules apply to realtime too.

Realtime subscriptions

wss://<ref>.<zone>/realtime/v1?apikey=<publishable key>

Order

1. On connect you receive ready 2. {"type":"subscribe","channel":"table:notes"} 3. When that table changes you receive change

What you must do first

Realtime has to be turned on for each table. A table you haven't turned on stays silent.

Turn it on with set_realtime { ref, table: "notes", enabled: true }, and check which tables are on with list_realtime_tables. In SQL, the statement you used on Supabase works as it is (SQL editor, run_sql, migrations):

alter publication supabase_realtime add table notes;

Realtime is turned on for that table once the SQL has run. drop table notes turns it off.

alter publication supabase_realtime add table notes, as you wrote it for Supabase, runs too. The SQL editor, run_sql and migrations take that statement out and turn realtime on for the table once the rest has run (drop table turns it off). Tables in the public schema only.

Only what you can see arrives

Change notifications also have to pass the access rules to be delivered. A row the publishable key cannot read never arrives over realtime either. That is the point of the feature.

Other messages

{"type":"broadcast","channel":"room:1","payload":{...}}: messages between people {"type":"presence","channel":"room:1","state":{...}}: who is connected

For both broadcast and presence you receive messages only after you subscribe to the channel. If you don't, you get an error telling you to subscribe first.

Settings and private channel rules

get_realtime_settings            on or off, public channels allowed, limits
set_realtime_settings            change them (only what is given, owners and admins)
list_realtime_policies           the realtime_messages table's rules
create_realtime_messages_table   make the table rules are written on
add_realtime_policy              add a rule template (signed-in-read | signed-in-write | own-channel)

With allow_public off only private channels work, and the realtime_messages table's rules decide who joins. Developers and above can add rules.