Docmill is an invoice generator API for automations. One HTTP request turns your
invoice data into a finished PDF — or an editable DOCX or
XLSX — using the built-in starter:invoice template or one the AI
drafts from a plain-language description. No template editor to learn, no credit math.
Free tier: 50 documents/month, no credit card. Self-serve signup, Stripe billing, cancel anytime.
Worked example
This is the whole integration. starter:invoice ships with every
account — line items, computed line totals, subtotal, tax, total due, and payment terms.
Send your data, get back %PDF bytes.
# render a PDF invoice from JSON — sync, binary response curl https://api.docmill.io/v1/documents \ -H "Authorization: Bearer dk_live_YOUR_KEY" \ -H "Content-Type: application/json" \ -d '{ "template_id": "starter:invoice", "output": "pdf", "data": { "invoiceNumber": "INV-2026-0142", "issueDate": "2026-08-28", "dueDate": "2026-09-27", "currency": "USD", "company": { "name": "Acme Studio LLC", "address": "100 Market St, Springfield", "email": "billing@acme.studio" }, "client": { "name": "Northwind Traders", "address": "1 Harbor Way, Portsmouth" }, "items": [ { "description": "Design sprint (2 weeks)", "quantity": 1, "unitPrice": 4800 }, { "description": "Implementation, hourly", "quantity": 32, "unitPrice": 120 }, { "description": "Hosting (annual)", "quantity": 1, "unitPrice": 360 } ], "subtotal": 9000, "taxRate": 8, "taxAmount": 720, "total": 9720, "notes": "Bank transfer to the account listed in the contract." } }' --output invoice.pdf # → invoice.pdf, ready to email or attach
Change "output": "pdf" to "docx" or "xlsx".
Docmill renders real Office files from templates with {{markers}} —
not a PDF pretending to be one.
Get the file inline as base64 instead of binary, or add ?async=1 for a
job API: it returns a job_id, you poll GET /v1/jobs/:id.
Built for batch invoice runs.
Describe it: POST /v1/templates/generate with a prompt like
“an invoice with EU VAT number and 30-day terms” returns a production template —
or paste an old invoice and Docmill converts it.
No-code & agent paths
You don't have to write the curl yourself. The connectors are free on every plan — your plan meters documents, nothing else.
n8n-nodes-docmill
Zapier — Generate Document action
Make — app with binary file output
MCP — @docmill/mcp-server for Claude & AI agents
REST — sync, base64, or async jobs
FAQ
Yes. Docmill's Free plan is $0 and includes 50 documents per month with a small watermark — enough to wire up an automation and run it in production before paying anything. No credit card required to start.
Yes — set "output": "docx" (or "xlsx" for spreadsheets).
Unlike PDF-only services, Docmill generates genuinely editable Office files from
DOCX/XLSX templates with {{markers}}, so your client can open the invoice
in Word and your accountant can open the ledger in Excel.
Install the community node n8n-nodes-docmill, add the Docmill node to
your workflow, paste your API key, pick starter:invoice (or your own
template), and map fields from previous nodes into the invoice data. The node outputs
the file as binary data ready for an email or storage node.
Strictly per document: one generated file costs one document, whatever the format or page count within reason. No credit blocks, no per-feature multipliers. Free $0 (50 docs/mo), Starter $19/mo (1,000), Growth $49/mo (5,000), Scale $99/mo (15,000) — Stripe billing, cancel anytime from the customer portal.
Yes. Describe the invoice in plain language and Docmill's AI generator returns a production template plus sample data showing exactly which fields to send. Every template is plain HTML/Handlebars underneath — inspect it, tweak it, own it.
Pricing
Count your invoices, pick a tier. Full details on the pricing section of the homepage.
Comparing tools? See how Docmill stacks up against APITemplate.io, CraftMyPDF, and PDFMonkey.
Read the docs, grab a free key, and your automation is emailing PDF invoices before lunch.