See llms.txt for all machine-readable content.

Back to Templates

Fill PDF forms from JSON data with JustFill and a form trigger

Created by

Created by: jusftfill.app || justfillapp
jusftfill.app

Last update

Last update 4 days ago

Categories

Share

Quick overview

Collect an existing PDF and JSON payload through an n8n form, upload it securely through a one-time URL, map JSON keys to reviewed JustFill template fields, fill the original PDF layout, and return a temporary download link.

How it works

  1. Triggers when a user submits an n8n form with a PDF upload and a “Data JSON” text payload.
  2. Calls the JustFill MCP API to request a one-time upload slot, then uploads the submitted PDF to the provided URL.
  3. Calls JustFill to open the uploaded PDF and retrieve its saved template field metadata.
  4. Parses the submitted JSON and matches its keys to JustFill template field names (case- and punctuation-insensitive), producing a field-ID-to-value map.
  5. Sends the mapped values to JustFill to fill the PDF and returns a temporary download URL for the generated file.
  6. Redirects the form response to the filled PDF download link.

Setup

  1. Create a JustFill account, generate an API key, and paste it into the workflow’s configuration value.
  2. Save a JustFill template for each PDF you plan to fill (with named fields) so the workflow can map JSON keys to those field names.
  3. Use the form trigger URL in n8n and decide how users will submit the PDF and JSON (or replace the form trigger with your preferred trigger in production).

Requirements

  • JustFill account and API key
  • A reviewed JustFill template with named fields for the exact PDF version
  • An n8n instance with Form Trigger, HTTP Request, and Code nodes

Customization

  • Replace the Form Trigger with Gmail, Google Drive, Dropbox, Airtable, or a webhook.
  • Move the JustFill API key from the Config node to an n8n credential or environment variable before production.
  • Extend the mapping node with aliases when source JSON keys differ from template field names.

Additional info

JustFill is a third-party service built by the template author. No AI model key is required after the PDF template has been reviewed and saved. Test with synthetic data before processing customer documents. Free JustFill downloads may contain a watermark, while paid plans provide clean PDFs. Download links are temporary. Never publish the workflow with a real A