Google Sheets Multi-Step Approvals to Slack (n8n Workflow)

Get a Slack alert only when your projects are fully approved—powered by Google Sheets + n8n

This n8n workflow monitors multi-step design and engineering sign-offs in Google Sheets and sends a single Slack notification only after All Approved is true—preventing duplicate alerts by marking each project as “Slack Notified” in your approval tracking sheet.

What this workflow does

• Design sign-off tracking: When a new row is added to your design sign-offs Google Sheets worksheet, the workflow matches the Project ID in the approval tracking Google Sheet and sets Design Approved to true.
• Engineering sign-off tracking: When a new row is added to your engineering sign-offs worksheet, it looks up the matching Project ID and sets Engineering Approved to true in the tracking sheet.
• Final approval + Slack notification: When a row in the approval tracking sheet is updated, the workflow checks whether All Approved is true and Slack Notified is not yet set.
• Single alert guarantee: If the project is fully approved, it sends a Slack message announcing completion and then updates the tracking row to set Slack Notified, so the same project won’t trigger duplicate notifications.

Use cases

• Notify your team in Slack immediately when a design + engineering review has fully cleared for a project.
• Reduce manual follow-ups by automating sign-off status updates in a centralized approval tracking Google Sheet.
• Ensure compliance-style auditability by recording each approval step and final notification state in the tracking sheet.

Technical details

• Google Sheets Trigger: Detects new design sign-off rows and new engineering sign-off rows.
• Google Sheets lookup + update: Finds records by Project ID and updates approval fields.
• if logic: Checks All Approved and whether Slack Notified is not yet set before sending the Slack message.
• Slack node: Sends the “fully approved” notification.

Setup requirements: Configure Google Sheets OAuth for both trigger and update nodes, select the correct spreadsheet/worksheets for design, engineering, and approval tracking, and ensure they share a Project ID column. In the tracking sheet, add fields for Design Approved, Engineering Approved, Slack Notified, and an All Approved field (commonly a formula).