n8n-nodes-pdf-form-filler

An n8n community node that fills AcroForm PDF fields with JSON data from your workflow.

Features

• Discover Fields — extract all form field names, types, options, and current values from any AcroForm PDF
• Fill Form — write values into text fields, checkboxes, radio groups, and dropdowns
• Static or dynamic mapping — define field mappings in the node UI or pass them as JSON at runtime
• Date formatting — automatic ISO date conversion with configurable format tokens (DD/MM/YYYY, etc.)
• Dot-notation data keys — access nested JSON values like applicant.address.postcode
• Warnings and observability — execution hints in the n8n UI, structured server-side logging

Installation

Self-hosted n8n

Install via the n8n GUI:

1. Go to Settings → Community Nodes
2. Enter n8n-nodes-pdf-form-filler
3. Click Install

Or install via the command line:

cd ~/.n8n
npm install n8n-nodes-pdf-form-filler

Restart n8n after installation. The node appears in the node panel as PDF Form Filler.

n8n Cloud

Not yet available on n8n Cloud. See docs/deployment.md for details.

Quick Start

1. Discover your PDF's fields

Create a workflow: Read Binary File → PDF Form Filler (Discover Fields)

The output JSON contains an array of all fields with their exact names, types, and available options.

2. Build your mapping

Each mapping entry connects a key in your JSON data to a field in the PDF:

{ "dataKey": "firstName", "pdfField": "A1-First name" }

Field names must match exactly (case-sensitive, whitespace-sensitive). Use the Discover Fields output to get the correct names.

3. Fill the form

Create a workflow: Read Binary File → Set Data → PDF Form Filler (Fill Form)

The node reads the PDF binary and your JSON data from the same input item, applies the mapping, and outputs a filled PDF binary.

Operations

Discover Fields

Returns metadata for every form field in the PDF.

Parameter	Type	Default	Description
PDF Binary Property	string	data	Binary property containing the PDF

Output: JSON with fields array and fieldCount. Each field has name, type, options, currentValue, and readOnly.

Fill Form

Fills PDF form fields with data from the input item.

Parameter	Type	Default	Description
PDF Binary Property	string	data	Binary property containing the PDF
Mapping Source	options	static	static (UI) or dynamic (from input JSON)
Field Mappings	fixedCollection	—	Mapping entries when using static mode
Dynamic Mapping Property	string	fieldMappings	JSON property name when using dynamic mode
Output Binary Property	string	data	Binary property name for the filled PDF
Output File Name	string	filled-form.pdf	Filename for the output PDF
Warn on Missing Values	boolean	true	Emit warnings for mapped fields with no data
Default Date Format	string	DD/MM/YYYY	Format for ISO date strings

Output: JSON summary (status, fieldsFilled, fieldsMissing, fieldsSkipped, fieldsErrored, warnings) plus the filled PDF as binary.

Supported Field Types

PDF Field Type	Input Value	Example
Text	string	"John Smith"
Checkbox	boolean	true / false
Radio Group	string (exact option)	"Three"
Dropdown	string (exact option)	"Single"

Date Formatting

ISO date strings (e.g. 2026-06-01) are automatically formatted using the configured date format. Supported tokens:

Token	Output	Example
DD	Day, zero-padded	01
D	Day, no padding	1
MM	Month, zero-padded	06
M	Month, no padding	6
YYYY	4-digit year	2026
YY	2-digit year	26

Set a per-field format with dateFormat on the mapping entry, or use Default Date Format for all fields.

Documentation

• User Guide — detailed usage instructions
• Field Mapping Guide — how to create and configure mappings
• Deployment Guide — installation, upgrading, requirements
• Operations Guide — troubleshooting, error reference, logging

Development

# Install dependencies
npm install

# Build
npm run build

# Run tests (156 tests)
npm test

# Run tests with coverage
npm test -- --coverage

# Lint
npm run lint

# Generate filled PDFs for manual verification
npm run test:manual

Local n8n testing

See docs/operations/local_testing.md for instructions on linking the node to a local n8n instance.

Architecture

Three-layer design: Node → Engine → Adapter

n8n Node Layer        — UI, binary I/O, n8n lifecycle
Engine Layer          — mapping resolution, type coercion, orchestration (pure TS, no n8n imports)
pdf-lib Adapter       — PDF load/save, field introspection, value writing

License

MIT