Airtable to PDF Invoices: n8n Workflow + Gmail Emailing

Automatically generate PDF invoices from Airtable and email them via Gmail—every day

This n8n automation workflow finds Airtable projects ready to invoice, validates the required invoice fields, generates a PDF invoice using an HTML-to-PDF API, then emails the PDF to the client with Gmail. It also updates Airtable to mark items as invoiced—or flags them as needing information.

What this workflow does

• Runs daily at your configured time.
• Queries Airtable for projects where status is ready_to_invoice and invoiced is false.
• Validates required fields for each project:
  • client_email and project_name
  • either fixed_fee or both hourly_rate and billable_hours
• If details are missing, updates the Airtable record status to needs_info.
• If details are complete, calculates subtotal, tax, and total and sets an invoice date.
• Builds an HTML invoice using project and configuration data.
• Sends the HTML to an external HTML-to-PDF API and receives the PDF.
• Emails the PDF invoice to the client using Gmail, then updates Airtable with the invoice date and invoice amount and marks the project as invoiced.

Use cases

• Send invoices automatically for service projects stored in Airtable—no manual PDF creation.
• Ensure billing accuracy by preventing sends when client email or fee/hour fields are missing (set to needs_info).
• For SaaS ops and automation engineers: standardize invoice delivery with a repeatable n8n workflow.

Technical details

• n8n nodes/logic: if, set, code, gmail, airtable, sticky note
• Airtable: uses an Airtable Personal Access Token plus your base ID and table name
• Gmail: Gmail OAuth2 to email the generated PDF from the configured sender mailbox
• PDF generation: external HTML-to-PDF API (HTML invoice → PDF response)

Setup note: ensure your Airtable table includes fields like status, invoiced, client_email, client_name, project_name, hourly_rate, billable_hours, and fixed_fee.