Feature Request: Enable client-side filtering on Realtime subscriptions for RLS-enabled tables without dropping payload

[Raphassith]

Documentation is

• Missing
• Outdated
• Confusing
• Not sure?

Explain in Detail

Currently, when Row Level Security (RLS) is enabled on a table, any attempt to use client-side filters in Realtime subscriptions (e.g., .on('postgres_changes', { filter: 'status=eq.1' })) fails because the database security context strips away the payload before the filter can evaluate it.

To bypass this and get filtered realtime updates, developers are forced to disable RLS and rely solely on GRANT/REVOKE permissions. However, this is not ideal for strict security practices.

Proposed Solution / Request:
Is there a way to optimize the Realtime engine (walrus) to securely evaluate simple client-side filters on RLS-enabled tables? This would immensely help developers achieve maximum security (keeping RLS enabled) while drastically saving network bandwidth by only streaming the exact matched payloads to the client.

Your Suggestion for Changes

No response

Documentation URL

No response

[spydon]

Thanks for a well-written issue! Triaging this: it isn't something the supabase-flutter client can address.

The client does no filtering or RLS evaluation of its own. When you call .onPostgresChanges(...), it just serializes the filter config (event, schema, table, and the filter string) and sends it over the websocket to the Realtime service. All of the actual filter evaluation, RLS enforcement, and payload construction happens server-side in the Realtime engine. So this feature request belongs on supabase/realtime rather than here.

A quick note on the premise: filtered postgres_changes on RLS-enabled tables does work in the general case, so it isn't accurate that RLS strips the payload before any filter can evaluate. The known limitations are more specific, and a few are already tracked server-side:

• Postgres changes with jsonb filters realtime#1090 — Postgres changes with jsonb filters
• docs(realtime): add MRE demonstrating JSONB filter limitation and col… realtime#1802 — docs MRE demonstrating the jsonb filter limitation

If you can share a minimal reproduction (table schema, RLS policy, and the exact filter you're using), it'll help pin down which limitation you're hitting. I'd recommend opening it on supabase/realtime, linking those issues.

Closing here since there's nothing actionable on the Flutter client.