Database Webhook Trigger Pattern

Configures Postgres triggers and database webhooks for event-driven architectures in Supabase.

Overview

This tile creates Postgres triggers that fire HTTP webhooks via pg_net when INSERT, UPDATE, or DELETE events occur on specified tables. Payloads are serialized with row_to_json. Triggers MUST scope UPDATE events to specific columns to prevent spurious firings. All DDL runs through MCP execute_sql.

Reference

pg_net HTTP Post Signature

SELECT net.http_post(
  url     := '<endpoint>',
  headers := '{"Content-Type": "application/json"}'::jsonb,
  body    := row_to_json(NEW)::text
);

Naming Conventions

Supported Events

• AFTER INSERT — fires on new row creation.
• AFTER UPDATE OF <columns> — fires on specific column changes only.
• AFTER DELETE — fires on row removal.

Dependencies

• supabase-mcp-verification (root prerequisite) — MUST pass before any trigger creation.
• pg_net extension — MUST be enabled for HTTP callouts.
• Target table — MUST already exist before trigger binding.

Composition Position

• Stage: database-runtime
• Priority: HIGH
• Runs after MCP verification and schema creation. Produces event-driven webhooks consumed by Edge Functions or external services.