Open source and self-hosted. Your own fields on every level, line items in groups, PDF templates in Liquid and EN 16931 e-invoices – in the browser, over a REST API and for AI agents over MCP.
One document, four stops. Everything you see here is the app itself, with demo data.
Pick the customer, put line items in groups and fill in your own fields. The preview renders the real PDF while you type, and every change is saved on its own.
Documents and the editor
Templates are HTML, CSS and Liquid, rendered to PDF on the server. Edit them in the browser, or download the toolkit and keep working in your own editor.
Templates
Before you finalize, openbill checks the document against EN 16931 and points to every missing detail, down to the field in your settings where it belongs.
E-invoices
Finalizing assigns the number and locks the document. openbill archives a PDF/A-3 with the factur-x.xml inside, and only a cancellation can change it from then on.
E-invoices
Templates are HTML, CSS and Liquid. Work on them in your own editor with a live preview, or describe the look and let an AI agent write it – it sees render errors with line numbers and checks the result before anything is saved.
Download the template toolkit and open Claude Code, Codex or another coding agent in its folder. The agent edits template.liquid and styles.css, the preview in your browser renders every save on your instance, and AGENTS.md tells it the rules. Happy with it? pnpm push saves it in openbill.
pnpm devpnpm pushpnpm pull
Connect an agent to the MCP server and it works on the template in place. It tries changes with sample data or a real document, reads errors with line numbers, the page count and missing fields, and saves once everything renders. The Liquid reference comes along as an MCP resource.
get-templaterender-template-previewupdate-template
Everything the app does works through a REST API with scoped tokens and an MCP server. An agent can draft an invoice, read the open issues and finalize it, with the same checks as you.
One compose file with everything it needs. Paste it into Dockge or Portainer (or save it as compose.yaml), change the four values at the top, deploy.
# openbill in one file, no .env needed. Paste it into Dockge or Portainer
# (or save it as compose.yaml), change the values below, deploy.
# Docs: https://openbill.dev/en/setup
x-openbill: &openbill-env
# public https address (your reverse proxy forwards it to port 7739)
APP_URL: https://invoices.example.com
# owner account, created on the first start (password: 8+ characters)
ADMIN_EMAIL: admin@example.com
ADMIN_PASSWORD: change-me
# database password: MariaDB keeps it from the first start on
DB_PASSWORD: &db-password change-me
# proxy on another host? Only its X-Forwarded-* headers count then:
# TRUSTED_PROXIES: 192.168.1.10
# openbill refuses to start while a password is still change-me.
# … and the services openbill, MariaDB and Gotenberg. Copy takes the whole file.