Justfill Pdf Forms
@mrmaciej1
Fill any PDF form with AI agents — ML field detection on scans, visual review loop, reusable templates, and native AcroForm fill via justfill.app.
概要
What is Justfill Pdf Forms?
Justfill Pdf Forms is an MCP server that lets AI agents (Claude, ChatGPT, n8n, or any MCP client) detect, review, and fill PDF form fields through justfill.app. It supports AcroForm fields, saved templates, and ML-based detection for scanned images.
How to use Justfill Pdf Forms?
Install the server with uv tool install ./mcp-server (or pip install ./mcp-server), then run justfill-mcp login to authorize once. Configure your MCP client with "command": "justfill-mcp". Alternatively, set the JUSTFILL_API_KEY environment variable or use JUSTFILL_EMAIL/JUSTFILL_PASSWORD as fallback. Tools include open_pdf, render_preview, fill_pdf, save_template, and field editing tools.
Key features of Justfill Pdf Forms
- Opens PDFs (including scanned images) and detects form fields
- Three resolution modes: saved template (deterministic), AcroForm (native), ML detection
- Confidence scores (0–1) for each ML-detected field, with raw score preserved
- Preview renders with color-coded field boxes and filled values before committing
- Field editing (add, update, remove) with batch operations and bulk pruning
- Saves reviewed layouts as templates for deterministic future fills
Use cases of Justfill Pdf Forms
- Fill a standard W-9 form with AcroForm fields automatically
- Process a scanned intake form, review and correct ML detections, then save as template
- Batch fill customer contracts after one-time template review
- Validate and adjust field positions on complex government forms before filling
- Automate form filling in n8n workflows or with a chatbot assistant
FAQ from Justfill Pdf Forms
How does the confidence score work?
ML confidence is calibrated from 0–1: ≥0.75 means the detector is sure, 0.4–0.75 is probably right (glance at preview), <0.4 is borderline. The raw detector score is kept as raw_score. A confidence of 1.0 means a saved template or AcroForm field is used (deterministic, no ML).
What authentication methods are supported?
You can log in interactively with justfill-mcp login (default), or provide a JUSTFILL_API_KEY (recommended), or fall back to JUSTFILL_EMAIL/JUSTFILL_PASSWORD. The server checks them in that order. Tokens auto-refresh on expiry.
What file types are accepted?
The open_pdf tool accepts PDF files, as well as scanned images (jpg, png, tiff) which are converted to PDF deterministically (so templates still match on the same image).
Is there a cost to use Justfill Pdf Forms?
Pricing follows justfill.app rules: template and AcroForm resolution are free. ML detection is free on the free plan (daily caps apply) and uses per-page credits on paid plans. Downloads consume the account's fill allowance/credits.
What limits exist in the server?
Only one PDF can be open at a time per server session (keeps field IDs stable). ML detection may have false positives/negatives; the correction loop (render_preview → field editing) exists to fix them.
