n8n PostgreSQL CDC Outbox Sync to HubSpot, Mailchimp & Slack

PostgreSQL changes, synced to HubSpot, Mailchimp, and Slack—automatically every minute

This n8n workflow monitors your PostgreSQL cdc_outbox for INSERT/UPDATE/DELETE events and reliably delivers them to HubSpot, Mailchimp, and Slack on a 1-minute schedule—with leasing, retries (exponential backoff), dead-lettering, and a webhook requeue endpoint for failed events.

What this workflow does

• Runs every minute and loads sync settings like batch size, which targets are enabled, and retry/backoff limits.
• Claims eligible rows from the PostgreSQL cdc_outbox table using a lease so multiple workers can process safely while preserving per-row ordering.
• Expands each change into delivery tasks for each enabled target:
  • HubSpot: upsert delivery (as configured)
  • Mailchimp: member sync and unsubscribe handling
  • Slack: notification delivery for events
• Sends tasks sequentially via HTTP requests and records whether each call succeeded, failed temporarily, or failed permanently.
• Updates event status back in PostgreSQL as delivered, scheduled for retry with exponential backoff, or dead-lettered.
• Dead-letter alerting: posts a Slack alert whenever events become dead.
• Requeue support: exposes POST /cdc-requeue to reset dead-lettered event IDs back to pending and returns how many were requeued.

Use cases

• Keep HubSpot and Mailchimp contacts in sync with live PostgreSQL customer data.
• Send Slack notifications when customer records change or when delivery fails permanently.
• Operationally recover from transient outages by requeuing dead-lettered events without rebuilding the pipeline.

Technical details

• Primary source: PostgreSQL cdc_outbox with capture function and trigger (created during manual setup).
• n8n components: if, set, code, no op, switch, webhook.
• Targets: HTTP-based delivery to HubSpot, Mailchimp, and Slack.

Perfect for n8n users and automation engineers who need dependable PostgreSQL CDC syncing with robust retry and failure recovery.