Auto Invoice Generation

Inside this workflow

Overview

**What it automates:** Monthly trigger → fetch project hours and rates → OpenAI generates invoice JSON (line items, totals, tax) → logged in Google Sheets → PDF generated and emailed to client. **Business outcome:** Manual invoicing is drudgery. This workflow saves 2 hours/month per project and eliminates typos. Faster invoicing = faster payment. **Apps & nodes:** Schedule (monthly), timesheet API, OpenAI (generation), Google Sheets (logging), Gmail (delivery), PDF generator **Setup (5 steps):** 1. Connect timesheet tool with project rates 2. Add OpenAI API key 3. Create Google Sheet for invoice log 4. Set up PDF generation 5. Connect Gmail **Difficulty:** Intermediate (18 min setup) | **Credentials:** Timesheet API, OpenAI, Google Sheets, Gmail, PDF service

What's included

Quickstart

1. 01

   Download the JSON

   With an active Library Pass, download the workflow file right from this page or your dashboard.

2. 02

   Import into n8n

   Choose Import from File and select the downloaded JSON. The full agent graph appears, ready to configure.

3. 03

   Plug in credentials

   Each integration node prompts for credentials on first run. The setup guide lists every credential the agent expects.

4. 04

   Activate and test

   Run once with sample input, confirm the expected output, then flip the activate toggle.

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