mrmaciej1/justfill-mcp

Let AI agents (Claude, ChatGPT, n8n — any MCP client) detect, review and fill
PDF form fields through justfill.app.
Fill PDF forms in ChatGPT
Install the published JustFill PDF Forms plugin
from the ChatGPT plugin directory, then connect your JustFill account. This
hosted path does not require installing the Python client or configuring an
MCP server manually.
Try this prompt with the one-page, six-field sample:
Ask for a filled preview with fictional values and approve it before generating
the PDF. Save the reviewed layout, then open the same original blank PDF for
the next client or project. Your saved template is available in the same
JustFill account; generated files follow that account's plan.
Try the two-project example and download the real editable results.
The example includes prompts for two fictional clients, the blank PDF, and
two generated PDFs with their free-output watermark.
Hosted server — no local installation
If your MCP client supports remote servers with OAuth, use this server URL:
Connect from your client, sign in to JustFill, and review the access request.
You do not need to install the Python package or copy an API key for this path.
Access can be revoked in JustFill under Account → API Keys.
Connection guide.
The client is MIT-licensed; PDF processing uses your JustFill account's allowance.
For a first check, use a blank form and fictional values, and review the filled
preview before exporting. Save the reviewed layout to reuse it with new data
when the same form comes up again.
Excel or CSV batch workflow
If the source data is already in a spreadsheet and you need one filled copy of
the same existing PDF per row, an MCP client is optional. The guided browser
workflow imports XLSX or CSV, maps columns to reviewed PDF fields, previews each
record, and exports the approved PDFs in a ZIP.
Try the five-row PDF mail merge sample
— no card or sales call.
Import-ready n8n workflows
Start with the
deterministic workflow JSON in this repository.
It collects a PDF and JSON payload, reuses the reviewed field names saved for
that exact form, fills the original layout and returns a temporary download
link.
The workflow is listed in the
n8n template library.
For new runs, import the current strict-mapping JSON from this repository,
which includes the synthetic fixture and validation evidence alongside it.
The workflow is free to download; running it uses a JustFill account and its
PDF-processing allowance. It uses built-in nodes, not the separate JustFill
community node.
The repository also includes the exact deterministic workflow JSON, synthetic
test PDF, production evidence and a separate two-pass vision workflow for an
unfamiliar form. Both call the hosted MCP endpoint with standard HTTP Request
nodes and can be inspected before adding credentials.
Inspect the source workflows and evidence, or follow the
step-by-step n8n setup.
Business example: recurring supplier intake
An operations team can keep the supplier's required intake PDF unchanged,
save its reviewed field layout once, and let n8n map approved vendor data from
a webhook or CRM record into that exact form. The workflow returns a temporary
filled-PDF link that can be reviewed before it is uploaded to Drive, attached
to a draft email, or written back to the vendor record. The repository's
synthetic supplier-intake PDF exercises this exact path without customer data.
Gemini CLI extension
Install the same reviewed MCP tools plus the included PDF workflow guidance: