n8n Workflow: Route Invoice Emails & Owner Digests to Gmail/Slack

Route invoice emails to Gmail—and send owner digests to keep duplicates & unknowns from slipping through

This n8n workflow simulates an invoice intake batch, matches each invoice to a customer, prepares invoice email payloads for Gmail delivery, and generates a single end-of-run owner digest highlighting duplicates and unknown customers that need attention.

What this workflow does

• Runs on demand or daily at 9:00: execute it by clicking Test workflow or follow the included schedule trigger.
• Loads a batch of invoice items from a demo intake source to mimic an invoice intake pipeline.
• Matches invoices to customers using an inline customer table, marking duplicates so the same invoice isn’t processed twice.
• Composes email payloads for sendable invoices (recipient, subject, body, and attachment filename).
• Creates owner alerts for invoices that are duplicates or belong to unknown customers, explaining why the invoice is not sent.
• Aggregates everything into one digest that reports counts and lists invoices needing attention after the run completes.

Use cases

• SaaS operators who want a reliable daily invoice intake simulation before wiring real sources.
• Automation engineers testing routing logic for invoice processing, duplicate detection, and exception handling.
• Teams preparing invoice outreach that need owner visibility via a single digest when customer matching fails.

Technical details

• Triggers: Manual trigger and Schedule trigger (daily at 9:00; configurable to your operating hours).
• Core nodes: if, code, merge, and a sticky note for workflow documentation.
• Integration path to real delivery: replace the demo intake and inline customer table with your real data sources; then add a Gmail or SMTP email node to send the composed payload (map to/subject/body/attachment fields). Owner alerts can be optionally routed to Slack or email.

Get a clean invoice routing workflow in n8n that’s designed to prevent duplicate sends and keep exceptions visible in one owner digest.