OpenAI Inbound Message Router with n8n, Slack & Google Sheets

OpenAI-powered inbound message routing for n8n — send sales to Slack, everything else to the right place

This n8n workflow receives inbound messages via a webhook, uses OpenAI to classify each message as sales, support, billing, spam, or other, and then routes the result to the appropriate destination—posting sales enquiries to Slack and sending unrecognized items to a Google Sheets review queue.

What this workflow does

• 1) Ingest inbound messages through a POST webhook. Your payload must include a message field (or map your incoming field to it).
• 2) Classify with OpenAI and return exactly one category label: sales, support, billing, spam, or other.
• 3) Normalize and flag off-list outputs by lowercasing the label and keeping letters only; anything not in the expected list is sent for manual review.
• 4) Route by category:
  • Sales messages are posted to a configured Slack channel.
  • Support and billing go to placeholder branches for you to implement your own processing.
  • Spam is dropped.
  • Unrecognized/off-list items are appended to a Google Sheets tab named needs_review.

Use cases

• SaaS teams that want instant triage: sales routed to Slack while support/billing is handled separately.
• Automation engineers building inbound intake systems without manual sorting.
• Operators who need a lightweight “human review” queue for ambiguous messages via Google Sheets.

Technical details

• Nodes/tech stack: webhook, OpenAI, code, no op, slack, switch, sticky note.
• OpenAI setup: add OpenAI credentials; classification works with gpt-4o-mini at temperature 0 (no reasoning model required).
• Slack integration: configure credentials and select the target channel for sales notifications.
• Google Sheets integration: add credentials, set YOUR_SHEET_ID, and ensure a sheet/tab named needs_review exists.