Build a leave request approval workflow in n8n with Google Sheets and Gmail

Description and use

An automated leave approval workflow in n8n uses Google Sheets, Gmail, and a free public holidays API to eliminate manual errors and accurately track leave balances.

Problem

Small companies manually process leave requests via email and spreadsheets, leading to errors and unclear balances.

Outcome

Automated leave approval reduces manual errors, ensures accurate leave balances, and provides clear audit trails.

Workflow

• Employee submits form with email, leave type, dates, half day, notes
• n8n counts real working days excluding weekends and public holidays, supports half days
• n8n checks remaining annual leave in Google Sheets and rejects impossible requests
• Manager receives email with Approve/Decline buttons; workflow waits up to three days
• If approved: balance updated, request logged, employee notified; if declined: logged and employee notified; if no reply: HR notified

Evidence

Most small companies handle holiday requests the same way: someone emails their manager, the manager replies "fine", and somebody is supposed to update a spreadsheet.

Source

This post shows how to build a proper leave approval workflow in n8n with nothing more than an n8n Form, Google Sheets, Gmail and a free public holidays API.

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The workflow counts real working days: weekends and your country's public holidays removed, half days supported.

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The manager gets an email with Approve and Decline buttons, and the workflow waits (up to three days).

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