n8n PDF-lib Custom Node

A custom n8n node for working with PDF documents using the pdf-lib library. This node allows you to fill PDF forms, create new PDFs, and merge multiple PDFs directly in your n8n workflows.

🎯 Features

• Fill PDF Forms - Add text overlays to existing PDF documents with full positioning control
• Fill Form Fields - Fill actual interactive PDF form fields (text, checkboxes, radio buttons)
• Extract Form Fields - Discover all form fields, types, values, and properties from PDFs ✨ NEW in v0.4.0
• Add Images - Embed PNG and JPEG images into PDFs with positioning and rotation
• Create PDFs - Generate new PDF documents from scratch
• Merge PDFs - Combine multiple PDF files into one with support for multiple sources
• JavaScript Code Mode - Programmatically define fields using JavaScript code
• French Character Support - Full UTF-8 support for international characters
• Flexible Input - Works with URLs or binary data
• Customizable - Configure fonts, colors, positions, sizes, and rotations

📦 Installation

Follow the detailed instructions in SETUP.md to install this custom node in your n8n instance.

Quick Start:

cd ~
wget https://github.com/n8n-io/n8n-nodes-starter/archive/refs/heads/master.zip
unzip master.zip
mv n8n-nodes-starter-master n8n-nodes-pdflib
cd n8n-nodes-pdflib

# Clean up examples
rm -rf nodes/ExampleNode nodes/HttpBin credentials/*

# Copy the PDF-lib node files into nodes/PdfLib/

# Update package.json with the provided version

# Build and link
npm install
npm run build
npm link

# Link to n8n
cd ~/.n8n/custom
npm link n8n-nodes-pdflib
docker restart n8n

🚀 Usage

Fill PDF Form

Perfect for filling tax receipts, invoices, or any form-based PDFs:

1. Select Fill PDF Form operation
2. Choose PDF source (URL or Binary Data)
3. Add text fields with coordinates and styling
4. Output as binary data

Example Use Case: French Tax Receipt (Reçu Fiscal)

• Load template PDF from URL
• Add donor name, address, amount, date
• Generate personalized receipt

Create PDF

Create new PDF documents from scratch:

1. Select Create PDF operation
2. Choose page size (A4, Letter, or Custom)
3. Add text fields with positions and styling
4. Output as binary data

Extract Form Fields ✨ NEW

Discover all form fields in a PDF before filling:

1. Select Extract Form Fields operation
2. Choose PDF source (URL or Binary Data)
3. Get JSON output with all field information

Returns:

• Field names and types (text, checkbox, radio, dropdown, list, button, signature)
• Current values and properties
• Max lengths, options, read-only status
• PDF metadata (page count, title, author)

Perfect for:

• Finding exact field names before filling forms
• Validating PDF form structure
• Building dynamic form-filling workflows
• Documenting form fields

Merge PDFs

Combine multiple PDF files:

1. Select Merge PDFs operation
2. Add multiple PDF sources (URL or Binary Data)
3. Get combined PDF as output

📋 Sample Workflow

A sample workflow for French tax receipts is included in sample-workflow.json. Import it into n8n to see the node in action.

The workflow:

1. Takes donation data (name, address, amount, date)
2. Fills a PDF template
3. Saves the result
4. Optionally emails it to the donor

🛠️ Files Included

• nodes/PdfLib/PdfLib.node.ts - Main node implementation
• nodes/PdfLib/PdfLib.node.json - Node metadata
• nodes/PdfLib/logo-full.svg - PDF-lib logo icon
• package.json - Package configuration
• SETUP.md - Detailed setup instructions
• PUBLISHING.md - Guide to publish to npm
• CHANGELOG.md - Version history
• sample-workflow.json - Example workflow
• README.md - This file

🔧 Configuration

Text Field Parameters

• Text - The text content to add
• X Position - Horizontal position from left (in points)
• Y Position - Vertical position from bottom (in points)
• Font Size - Text size (default: 12)
• Page Number - Which page to add text to (0-indexed)
• Color - Text color in hex format (e.g., #000000)

Coordinate System

PDFs use a coordinate system where:

• (0, 0) is at the bottom-left corner
• X increases to the right
• Y increases upward
• A4 page is approximately 595 x 842 points

🎨 Customization

You can extend this node by:

• Adding more PDF operations (rotate, extract, compress)
• Supporting more fonts (embed custom TTF fonts)
• Adding image support
• Creating credential support for authenticated sources

📚 Resources

• pdf-lib Documentation
• n8n Community Nodes
• n8n Workflow Automation

🐛 Troubleshooting

Node doesn't appear:

• Verify npm link worked: ls -la ~/.n8n/custom/node_modules
• Check Docker logs: docker logs n8n
• Restart n8n: docker restart n8n

Build errors:

• Delete node_modules and reinstall: rm -rf node_modules package-lock.json && npm install
• Ensure TypeScript is installed: npm install -g typescript

PDF operations fail:

• Check URL accessibility from Docker container
• Verify coordinates are within page bounds
• Check n8n execution logs for details

📄 License

MIT

🤝 Contributing

This is a custom node for personal/organizational use. Feel free to modify and extend it for your needs!

✨ Advantages

✅ Permanent - Survives n8n updates
✅ Local - No external API dependencies
✅ Fast - Runs directly in n8n
✅ Flexible - Full control over PDF operations
✅ Reusable - Works across all workflows
✅ Team-Friendly - Easy for others to use