n8n Error Workflow: Route Failures by Severity to Slack & Sheets

Route n8n workflow errors by severity—send critical alerts to Slack, log bad inputs to Google Sheets, and forward transient failures to a webhook

If your n8n automations fail, you shouldn’t sift through execution logs manually. This n8n Error Workflow automatically catches failures from other workflows, classifies each incident (credentials, bad-input, transient, or unclassified), and routes the right alerts to the right destination—Slack, Google Sheets, or your custom HTTP endpoint.

What this workflow does

• Triggers on workflow failure whenever another workflow has this workflow configured as its n8n Error Workflow.
• Extracts failure details such as workflow name, execution URL, failing node, error message, and HTTP status.
• Classifies severity from the error message and HTTP status, grouping incidents into:
  • Credentials (high urgency)
  • Bad-input (needs data cleanup)
  • Transient (may resolve on retry)
  • Unclassified (catch-all)
• Routes alerts by type:
  • Credentials-related failures → posts a high-urgency Slack message to your configured channel.
  • Bad-input failures → appends rows to Google Sheets for later review.
  • Transient and unclassified failures → sends a JSON payload to your HTTP endpoint (via the catch-all branch).

Use cases

• Notify your team immediately when authentication/credential issues break critical automations (e.g., Slack, Gmail, APIs).
• Build a backlog of bad-input errors in Google Sheets to improve validation and cleanup processes.
• Forward transient failures to downstream incident handling (retry queues, monitoring, or ticketing) via an HTTP webhook.

Technical details

• Integrations / nodes used: code, switch, sticky note, Slack, Google Sheets, and optional branches for Gmail and Notion.
• Configuration: set the monitored workflows’ Error Workflow to this workflow.
• Webhook: use the environment variable ERROR_ALERT_WEBHOOK_URL (replace the default if needed).
• Optional enhancements: configure Gmail notifications or Notion incident pages (Gmail recipient + Notion database).