BillingEngine

BillingEngine MCP server

Create customers and invoices, look up open invoices and record payments in BillingEngine by talking to Claude, Cursor or any other MCP client:

"Create an invoice for Acme Painting over 100 euros."

"Which invoices are overdue?"

"Acme paid invoice 2610030028, record the payment."

BillingEngine is invoicing software for freelancers and small businesses with e-invoicing (EN 16931, XRechnung, ZUGFeRD / Factur-X). The server is a thin layer over the BillingEngine API and runs on your computer.

Requirements

• Node.js 20 or newer
• A BillingEngine account on a paid plan. The API is not available in the Free plan.
• Your API key from Settings > API in BillingEngine

Setup

Claude Desktop

Add this to claude_desktop_config.json:

{
  "mcpServers": {
    "billingengine": {
      "command": "npx",
      "args": ["-y", "billingengine-mcp"],
      "env": { "BILLINGENGINE_API_KEY": "your-api-key" }
    }
  }
}

Claude Code

claude mcp add billingengine --env BILLINGENGINE_API_KEY=your-api-key -- npx -y billingengine-mcp

Cursor and other clients

Use the same command, args and env as above in the MCP settings of your client.

Tools

Tool	What it does
find_customers	Searches customers by company, name or email
create_customer	Creates a customer
update_customer	Changes a customer
create_invoice	Creates a draft invoice for a customer
update_invoice	Changes a draft invoice
list_invoices	Lists invoices, filtered by status, customer, number or date
get_invoice	Returns one invoice with items and payment status
download_invoice	Saves the PDF or the XML e-invoice to your Downloads folder
record_payment	Records a payment for sent invoices
list_payments	Lists payments, optionally for one invoice

What it does and does not do

• Invoices are created as drafts. Nothing is sent to your customers; you review and send the invoice in BillingEngine. Every result contains a link to open the draft.
• Prices are net. Number, language, texts, VAT treatment and payment terms come from your account settings, exactly as in the invoice form.
• Nothing can be deleted through this server.
• New invoices count towards the monthly invoice maximum of your plan.
• The API allows 60 requests per minute per key.
• Your key stays on your computer and is only sent to BillingEngine.

If a key is ever exposed, generate a new one under Settings > API. The old key stops working immediately. The settings also show when the key was last used.

Configuration

Variable	Meaning
BILLINGENGINE_API_KEY	Your API key (required)
BILLINGENGINE_URL	Base URL, defaults to https://www.billingengine.com

Development

npm install
npm run build
BILLINGENGINE_API_KEY=... node dist/index.js

License

MIT. BillingEngine itself is a commercial service; see billingengine.com.