Realtime channel reports SUBSCRIBED but no postgres_changes events fire for inserts or updates
appears when:After adding a .channel().on('postgres_changes', ...) handler that connects successfully but never receives a row
Supabase Realtime not working
Realtime sits on top of logical replication and RLS. If replication is off, or your SELECT policy blocks the row, or the JWT expired, the subscription is silent.
supabase_realtime publication, the authenticated user has no SELECT policy covering the changed row, the JWT on the channel has expired, or a React cleanup is missing so stale handlers drop events. Fix all four in order.Quick fix for Supabase Realtime not working
01// app/hooks/useTasksRealtime.ts — typed subscription with cleanup and auth refresh02import { useEffect, useState } from "react";03import { createClient } from "@supabase/supabase-js";04 05const supabase = createClient(06 process.env.NEXT_PUBLIC_SUPABASE_URL!,07 process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,08);09 10export function useTasksRealtime(userId: string) {11 const [tasks, setTasks] = useState<Task[]>([]);12 13 useEffect(() => {14 const channel = supabase15 .channel(`tasks:${userId}`)16 .on(17 "postgres_changes",18 { event: "*", schema: "public", table: "tasks", filter: `user_id=eq.${userId}` },19 (payload) => {20 if (payload.eventType === "INSERT") setTasks((t) => [...t, payload.new as Task]);21 if (payload.eventType === "DELETE") setTasks((t) => t.filter((x) => x.id !== payload.old.id));22 },23 )24 .subscribe();25 26 // refresh the JWT on every auth event so RLS stays accurate27 const { data: sub } = supabase.auth.onAuthStateChange((_event, session) => {28 if (session?.access_token) supabase.realtime.setAuth(session.access_token);29 });30 31 return () => {32 supabase.removeChannel(channel);33 sub.subscription.unsubscribe();34 };35 }, [userId]);36 37 return tasks;38}39 40type Task = { id: string; user_id: string; title: string };Deeper fixes when the quick fix fails
01 · Enable replication via SQL migration (reproducible)
01-- supabase/migrations/20260417_enable_tasks_realtime.sql02-- Add the table to the built-in supabase_realtime publication03alter publication supabase_realtime add table public.tasks;04 05-- If you also stream UPDATEs and DELETEs, ensure the REPLICA IDENTITY06-- is FULL so the payload includes old values (Supabase default is DEFAULT)07alter table public.tasks replica identity full;08 09-- Matching SELECT policy so the user can read events about their own rows10create policy "users read own tasks"11on public.tasks12for select13to authenticated14using (auth.uid() = user_id);02 · Typed subscription wrapper that handles lifecycle
01// lib/realtime.ts — generic subscribe helper with cleanup built in02import type { RealtimeChannel, SupabaseClient } from "@supabase/supabase-js";03 04type ChangePayload<T> =05 | { eventType: "INSERT"; new: T; old: null }06 | { eventType: "UPDATE"; new: T; old: T }07 | { eventType: "DELETE"; new: null; old: T };08 09export function subscribeToTable<T>(10 supabase: SupabaseClient,11 table: string,12 filter: string,13 onChange: (p: ChangePayload<T>) => void,14): () => void {15 const channel: RealtimeChannel = supabase16 .channel(`${table}:${filter}`)17 .on("postgres_changes", { event: "*", schema: "public", table, filter }, (raw) => {18 onChange(raw as unknown as ChangePayload<T>);19 })20 .subscribe();21 22 return () => {23 supabase.removeChannel(channel);24 };25}03 · Debug the drop reason in Realtime logs
Dashboard → Logs → Realtime. Filter by your channel id. Every dropped event is logged with a reason — rls_violation, no_policy, or publication_missing. This is faster than guessing. If logs show rls_violation but your policy looks correct, confirm the JWT on the channel with supabase.realtime.accessToken and ensure it matches the expected user.
Why AI-built apps hit Supabase Realtime not working
Supabase Realtime is a layer on top of Postgres logical replication and the built-in Realtime server. When a row changes, Postgres writes a WAL entry, the Realtime service reads the WAL, evaluates RLS against every subscribed connection, and forwards the event only to clients that should see the row. Three separate things must be true for the event to arrive in your browser: replication enabled on the table, RLS permitting SELECT for the subscriber, and the channel carrying a valid user JWT.
AI builders wire up the client SDK with supabase.channel().on(...) and stop there. The table is not added to the supabase_realtime publication by default. The channel reports SUBSCRIBED because the websocket handshake succeeded, but Postgres never streams the changes into the Realtime service. Nothing ever arrives. The fix is two lines of SQL or one toggle in the Supabase Dashboard under Database → Replication.
The second common failure is RLS. Realtime evaluates your SELECT policy against each subscriber. If the subscriber is anonymous and your policy requires auth.uid() = user_id, the row is filtered and the event is dropped silently. AI-generated code commonly sets up Realtime with the anon key before the user signs in, or forgets to call supabase.realtime.setAuth after the user authenticates. The channel stays alive on the stale identity and events never reach the handler.
The third failure is React cleanup. useEffect must return a function that calls supabase.removeChannel(channel). Without it, every route change or strict-mode remount leaks a new channel. Two channels get every event, one of which updates the stale state from the unmounted component. The user sees duplicate rows or ghost updates.
Supabase Realtime not working by AI builder
How often each AI builder ships this error and the pattern that produces it.
| Builder | Frequency | Pattern |
|---|---|---|
| Lovable | Every Realtime scaffold | Adds subscribe() but never enables replication on the table |
| Bolt.new | Common | Subscribes with anon key before user signs in; never calls setAuth |
| Base44 | Common | No SELECT policy — RLS silently drops every event |
| Cursor | Sometimes | useEffect with no cleanup leaks duplicate channels in strict mode |
| Replit Agent | Rare | Uses REPLICA IDENTITY DEFAULT so UPDATE payloads are missing old values |
Related errors we fix
Stop Supabase Realtime not working recurring in AI-built apps
- →Add tables to supabase_realtime via SQL migration, not the dashboard — config drifts otherwise.
- →Pair every Realtime subscription with a matching SELECT policy in the same commit.
- →Always call supabase.realtime.setAuth inside onAuthStateChange to keep RLS accurate.
- →Return supabase.removeChannel from every useEffect; ESLint rule `react-hooks/exhaustive-deps` is not enough.
- →Add an integration test that inserts a row and asserts the subscriber receives it within 2 seconds.
Still stuck with Supabase Realtime not working?
Supabase Realtime not working questions
Why does my Supabase Realtime subscription connect but never fire?+
Does Row Level Security affect Realtime?+
What does Realtime do when my Supabase access token expires?+
Why do I see duplicate Realtime events in React?+
How long does a Supabase Realtime fix take?+
Ship the fix. Keep the fix.
Emergency Triage restores service in 48 hours. Break the Fix Loop rebuilds CI so this error cannot ship again.
Hyder Shah leads Afterbuild Labs, shipping production rescues for apps built in Lovable, Bolt.new, Cursor, Replit, v0, and Base44. our rescue methodology.