n8n Stale Workflow Alerts via API & Gmail (HTTP Request)

Stay on top of failed and “stale” n8n workflows—automatically alert via Gmail

This n8n workflow monitors a specific workflow’s latest execution using the n8n REST API and sends a Gmail alert when the run fails or hasn’t successfully completed within the expected time window. Designed to help SaaS operators and automation engineers catch issues early—every 6 hours.

What this workflow does

• Runs on a 6-hour schedule using a schedule trigger.
• Fetches the latest execution for your configured workflow ID by calling the n8n REST API via an HTTP Request node.
• Detects “stale” executions by calculating the number of hours since the last execution finished (or started), then comparing it against the expected run interval plus a grace period.
• Determines whether attention is needed when either:
  • the latest execution status is non-success, or
  • the execution is considered stale (didn’t succeed in the defined time window).
• Sends a Gmail alert when the monitor status indicates attention is required.

Use cases

• Alert your team when a critical automation pipeline in n8n fails (e.g., data sync, provisioning, reporting jobs).
• Detect silent failures where a workflow stops running or lags behind its expected schedule.
• Keep operational visibility for multi-workflow n8n setups by monitoring one workflow at a time via workflow ID.

Technical details

• Schedule Trigger: runs every 6 hours.
• HTTP Request: calls the n8n REST API (use your YOUR_N8N_API_KEY and set YOUR_WORKFLOW_ID).
• Code: calculates elapsed hours since the last execution and evaluates stale conditions.
• If: applies logic to decide whether to alert based on status and staleness.
• Gmail: sends the email using Gmail OAuth2; configure the recipient in the Gmail node’s sendTo field.

Set up the n8n instance URL (currently http://localhost:5678) so the HTTP Request node can reach it from where this workflow runs.