supabase-webhooks-events

# Supabase Webhooks & Database Events ## Overview Supabase offers four complementary event mechanisms: **Database Webhooks** (trigger-based HTTP calls via `pg_net`), **`supabase_functions.http_request()`** (call Edge Functions from triggers), **Postgres LISTEN/NOTIFY** (lightweight pub/sub), and **Realtime `postgres_changes`** (client-side event subscriptions). This skill covers all four patterns with production-ready code including signature verification, idempotency, and retry handling. ## Prerequisites - Supabase project (local or hosted) with `supabase` CLI installed - `pg_net` extension enabled: Dashboard > Database > Extensions > search "pg_net" > Enable - `@supabase/supabase-js` v2+ installed for client-side patterns - Edge Functions deployed for webhook receiver patterns ## Step 1 — Database Webhooks with `pg_net` and Trigger Functions Database webhooks fire HTTP requests when rows change. Under the hood, Supabase uses the `pg_net` extension to make async, non-blocking HTTP calls from within PostgreSQL. ### Enable pg_net and Create the Trigger Function ```sql -- Enable the pg_net extension (one-time) CREATE EXTENSION IF NOT EXISTS pg_net WITH SCHEMA extensions; -- Trigger function: POST to an Edge Function on every new order CREATE OR REPLACE FUNCTION public.notify_order_created() RETURNS trigger AS $$ BEGIN PERFORM net.http_post( url := 'https://<project-ref>.supabase.co/functions/v1/on-order-created', headers := jsonb_build_object( 'Conte...