JustFill PDF Form Automation MCP server

JustFill MCP Server

Let AI agents (Claude, ChatGPT, n8n — any MCP client) detect, review and fill PDF form fields through justfill.app.

<!-- mcp-name: io.github.mrmaciej1/justfill-pdf-forms -->

Hosted server — no local installation

If your MCP client supports remote servers with OAuth, use this server URL:

https://justfill.app/api/mcp

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 corrected workflow is also available in the n8n template library. 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:

gemini extensions install https://github.com/mrmaciej1/justfill-mcp

The extension manifest lives at the repository root and uses the published justfill-mcp package. Gemini CLI asks for normal third-party extension consent before enabling it.

Why agents can trust it

Shortened. The full README is on GitHub.