JustFill × n8n

Fill existing PDF forms from any n8n workflow.

Start with Excel, Google Sheets, CRM records, a database, or a webhook. JustFill handles the PDF geometry and returns a filled document; n8n controls everything before and after it.

Open the n8n template Run the included example

Available in the n8n template library. The workflow is free to download; running it requires a JustFill account and uses its PDF-processing allowance. Source and setup on GitHub

The boundary is deliberate

Your source

Sheets, CRM, webhook, database

JustFill MCP

Detect, map, fill, reuse template

Your destination

Drive, approval, email, downstream API

JustFill does not send emails, submit forms, or update third-party systems on its own. That keeps each external side effect visible and configurable in your n8n workflow.

First run

Run the three-field example first.

The imported workflow already contains the HTTP Request and Code nodes. It does not require the separate JustFill community node. No AI Agent or MCP Client Tool node is needed for this example. The sample PDF has three named fields, so this first check needs no AI detection or separate model key.

Running it still uses your JustFill PDF-processing allowance. The output may have a watermark depending on your account. Use the made-up data below, not a customer document, for this first check.

Step 1
Import the deterministic workflow
If you already imported “Fill PDF with JustFill”, keep that workflow. Otherwise, Download the workflow JSON and import it into n8n. Keep the workflow inactive while testing.
Step 2
Add your JustFill key
Open Account → API Keys. Sign in or create an account, verify your email, then create a key and replace the placeholder in Config. Config stores the key as plain text: never share that export. Use an n8n credential before production use.
Step 3
Use the sample PDF and JSON
Download the sample PDF. Run the workflow manually, upload that PDF in the test form, and paste this into Data JSON:
```
{
  "company_name": "Northwind LLC",
  "vendor_reference": "V-1042",
  "remittance_email": "ap@northwind.example"
}
```
Step 4
Check the returned PDF
Check all three values in the PDF. In Result, inspect output_mode and warnings before sharing the file. The download link is temporary. For your own recurring PDF, review and save its field names once, then adapt the JSON to those names; unknown or ambiguous names stop the workflow.

AI-assisted first run

Useful when the form is new or field labels need interpretation. Keep preview and approval in the loop until the layout is reviewed.

Deterministic repeat runs

Best for recurring business forms. A saved template bypasses field detection and makes the mapping stable as long as the PDF itself is unchanged.

Validate the spreadsheet workflow first

Need one existing PDF per Excel row, without building n8n yet?

Use the five-row browser sample to check field detection, column mapping, review, and ZIP export. Move the proven recurring template into n8n afterwards.

Try the Excel → PDF sample

Frequently asked questions

Does the workflow require an AI agent?

No. For a recurring PDF, save the reviewed layout as a template and call the JustFill MCP tools in a deterministic n8n workflow. An AI Agent node is optional.

Can n8n use Excel, Google Sheets, a CRM, or a webhook as input?

Yes. n8n prepares the values from any upstream node. JustFill receives the PDF and the final field-value mapping, then returns a filled PDF link.

Does JustFill email or submit the PDF automatically?

No. JustFill returns the filled PDF. Your n8n workflow decides whether to store it, email it, request approval, or pass it to another system.

What happens when the PDF layout changes?

The saved template is tied to the exact document content. Open and review the changed PDF once, then save a new template before resuming automated fills.