Automate invoice creation and delivery with Google Sheets, Invoice Ninja and Gmail

⚙️ How It Works

This workflow automates the repetitive task of invoicing, turning a manual process into an efficient, hands-free operation.

✅ Trigger

The workflow is automatically activated when a new row is added or updated in your Google Sheet with the status Ready for Invoice.

🧾 Create Invoice

The workflow sends project data to your invoicing service (e.g., Invoice Ninja) using an HTTP Request node to generate a professional invoice.

📧 Send Email

The generated invoice is attached to an email and sent to the client using the Gmail node.

📝 Update Status

Finally, the workflow updates the Status field in Google Sheet to Invoiced, marking the process complete and recorded.

🛠️ How to Set Up

1. Install the Workflow

• Copy the provided workflow JSON.
• In your n8n instance, go to Workflows > New.
• Click Import from JSON and paste the JSON.
• Save the workflow.

2. Prepare Your Google Sheet

Create a Google Sheet to act as your project database. It must include the following columns:

Ensure the data is accurate and matches your workflow expressions.

3. Configure Credentials

🟡 Google Sheets Trigger & Update Node

• Add your Google Sheets OAuth2 credentials.
• In both the trigger node and update node, select:
  • Correct Spreadsheet ID
  • Correct Sheet Name

🔵 HTTP Request Node (Invoice API)

• Add your API Key (e.g., from Invoice Ninja) in the request URL.
• Adjust:
  • The URL endpoint
  • The JSON body

Based on your invoicing service’s API documentation.

🔴 Gmail Node

• Add your Gmail OAuth2 credentials.

4. Customize the Workflow

🔧 HTTP Request Node

• Replace YOUR_INVOICE_NINJA_API_KEY with your real API key.
• Ensure expressions like {{ $json['Client Email'] }} match the exact column headers in your Google Sheet.

💌 Gmail Node

• Customize:
  • From Email
  • Subject
  • Email body (HTML or text)

Tailor the content to match your brand and tone.

5. Activate the Workflow

Once everything is configured:

• Click the Inactive toggle (top-right) to activate the workflow.

Now your invoicing process is fully automated!