n8n Form Trigger: Generate Invoice PDFs with MintPDF + Gmail

Turn an n8n Form submission into a ready-to-send invoice PDF—instantly

This n8n workflow captures invoice details from an n8n Form Trigger, generates a numbered HTML invoice, renders it to a PDF using MintPDF, then emails the PDF via Gmail and returns the same PDF for immediate download.

What this workflow does

• Receives invoice requests from an n8n form submission including customer details, billing address, line items, and optional notes.
• Adds your invoice settings (seller details, currency, tax rate, payment terms, and invoice prefix) to the incoming data.
• Validates, parses, and calculates totals, computing amounts in integer cents to generate accurate invoice totals.
• Generates an invoice number and due date, then builds the invoice as HTML with the final values.
• Renders the HTML to a PDF with MintPDF as an A4 document, including a footer and page numbers.
• Sends the PDF invoice by email using Gmail, including the invoice number, amount due, and due date in the message.
• Returns the PDF to the form submitter so they can download the invoice right after submission.

Use cases

• SaaS operators who need a lightweight invoice generation workflow without manual PDF creation.
• Freelancers and agencies collecting invoice details via a form and immediately sending a PDF to clients.
• Automation engineers building a customer-facing workflow that turns structured form input into MintPDF-rendered invoices.

Technical details

• Nodes / integrations: Form, Code, Gmail, and n8n-nodes-mintpdf (MintPDF)
• Setup: Install the community node package n8n-nodes-mintpdf and configure a MintPDF API credential from mintpdf.dev.
• Email: Connect a Gmail OAuth2 credential for sending the invoice PDF attachment.
• Invoice settings: Update seller details, currency, tax rate, payment terms, and invoice prefix.