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Version: v2 RC

on().subscribe()

supabase
.channel('*')
.on('postgres_changes', { event: '*', schema: '*' }, payload => {
console.log('Change received!', payload)
})
.subscribe()

Parameters

  • typerequiredstring

    "postgres_changes" is the only type supported at this time

  • filterrequiredobject

    An object with an event property and a schema property. Event property can be *, insert, create, update, or delete.

  • callbackrequiredFunction

    A callback function that will be called when the channel receives a message.

Notes

  • Realtime is disabled by default for new Projects for better database performance and security. You can turn it on by managing replication.
  • Row level security is not applied to delete statements.
  • If you want to receive the "previous" data for updates and deletes, you will need to set REPLICA IDENTITY to FULL, like this: ALTER TABLE your_table REPLICA IDENTITY FULL;
  • When a delete occurs, the contents of old_record will be broadcast to all subscribers to that table so ensure that each table's replica identity only contains information that is safe to expose publicly.
  • The channel name must exactly match the schema/table/filter you want to listen to separated by colons. See below examples for additional context.

Examples

Listen to all database changes

supabase
.channel('*')
.on('postgres_changes', { event: '*', schema: '*' }, payload => {
console.log('Change received!', payload)
})
.subscribe()

Listening to a specific table

supabase
.channel('public:countries')
.on('postgres_changes', { event: '*', schema: 'public', table: 'countries' }, payload => {
console.log('Change received!', payload)
})
.subscribe()

Listening to inserts

supabase
.channel('public:countries')
.on('postgres_changes', { event: 'INSERT', schema: 'public', table: 'countries' }, payload => {
console.log('Change received!', payload)
})
.subscribe()

Listening to updates

By default, Supabase will send only the updated record. If you want to receive the previous values as well you can enable full replication for the table you are listening to:

alter table "your_table" replica identity full;
supabase
.channel('public:countries')
.on('postgres_changes', { event: 'UPDATE', schema: 'public', table: 'countries' }, payload => {
console.log('Change received!', payload)
})
.subscribe()

Listening to deletes

By default, Supabase does not send deleted records. If you want to receive the deleted record you can enable full replication for the table you are listening too:

alter table "your_table" replica identity full;
supabase
.channel('public:countries')
.on('postgres_changes', { event: 'DELETE', schema: 'public', table: 'countries' }, payload => {
console.log('Change received!', payload)
})
.subscribe()

Listening to multiple events

You can chain listeners if you want to listen to multiple events for each table.

supabase
.channel('public:countries')
.on('postgres_changes', { event: 'INSERT', schema: 'public', table: 'countries' }, handleRecordInserted)
.on('postgres_changes', { event: 'DELETE', schema: 'public', table: 'countries' }, handleRecordDeleted)
.subscribe()

Listening to row level changes

You can listen to individual rows using the format {table}:{col}=eq.{val} - where {col} is the column name, and {val} is the value which you want to match.

supabase
.channel('public:countries:id=eq.200')
.on('postgres_changes', { event: 'UPDATE', schema: 'public', table: 'countries', filter: 'id=eq.200' }, handleRecordUpdated)
.subscribe()