n8n Webhook: Generate PDF Invoices from JSON with PDFMint

Generate professional PDF invoices from JSON—directly via an n8n webhook

This n8n Webhook workflow accepts invoice data as a JSON payload, merges it with your seller defaults, renders an invoice in HTML/CSS, converts it to a PDF using PDFMint, and returns the generated PDF as a binary file in the same HTTP response.

What this workflow does

• Receives a POST request on an n8n webhook endpoint (path: /invoice) containing customer details, line items, and optional invoice fields.
• Applies seller defaults and fills missing values such as currency, invoice number, issue date, and due date.
• Builds the invoice content by rendering an invoice in plain HTML/CSS, calculating each line total and the grand total.
• Converts HTML/CSS to PDF using the PDFMint community node.
• Returns the PDF immediately in the webhook response (no separate download step required).

Use cases

• SaaS billing: generate invoices on-demand from your application by POSTing invoice JSON to n8n.
• Marketplace payouts: create customer-ready PDF invoices for line-item transactions.
• Freelance ops: automate recurring invoice generation while keeping invoice layout under your control via HTML/CSS.

Technical details

• Nodes / workflow components: set, webhook, sticky note, n8n-nodes-pdfmintpdf (PDFMint community node), respond to webhook.
• PDFMint credentials: create a PDFMint API key (from pdf.mintapis.com) and add it as a PDFMint credential in n8n.
• Self-host required: this template uses the PDFMint community node, which n8n Cloud cannot install, so self-hosted n8n is required.
• Customization: edit the markup directly in the “Build invoice HTML” step to change the invoice design; line items render from the provided JSON.