Webhook providers use at-least-once delivery.

If a request times out or fails, they retry — which can cause the same workflow to execute twice.

That means duplicated side effects: – duplicate payments – duplicate emails – duplicate database writes

This template adds an idempotency gate before any side effect runs.

The first event goes through. Retries are blocked.

The workflow was recently approved and published in the official n8n template library: https://n8n.io/workflows/13863