Developers

Your books, for your software.

AI assistants connect over MCP; your own code calls the REST API. Both read the books and suggest entries. Nothing they send changes the books until a person approves it.

Connect an AI assistant

Claude, ChatGPT, Cursor and other assistants that take remote MCP servers can add BillingEase as a custom connector.

https://billingease.app/mcp

Add that address as a connector. The assistant opens BillingEase in your browser: sign in, pick the business, and choose what it may do. It works with OAuth 2.1 and PKCE, finds everything it needs from the server itself, and needs no client secret. You can disconnect it any time in Settings → Apps and API.

It gets 25 tools for reading (invoices, customers, spending, bills, suppliers, the home page totals) and 5 for suggesting: propose_expensepropose_billpropose_payment_receivedpropose_bill_paymentpropose_reminder. Suggestions wait in For you to check.

Call the REST API

Make a personal access token in Settings → Apps and API, then send it as a Bearer token.

curl https://billingease.app/v1/invoices?status=late \
  -H "Authorization: Bearer be_pat_…"

curl https://billingease.app/v1/proposals \
  -H "Authorization: Bearer be_pat_…" \
  -H "Content-Type: application/json" \
  -d '{"kind": "expense.create",
       "title": "Ochre Café, £12.40",
       "summary": "Card receipt from the team lunch",
       "payload": {"spentOn": "2026-10-09", "payee": "Ochre Café",
                   "categoryId": "travel", "gross": 1240, "vat": 0, "method": "Card"}}'

Money is always whole minor units: 1240 is £12.40 (or 12.40 in rupees or dollars). Dates are YYYY-MM-DD.
A token works for one business, as the person who made it, with their role.
Errors come back as {"error": {"code", "message", "fields"}}, with a reason a person can read.
Limits: a number of calls per minute per token, and per day per business. Over them you get 429 and a Retry-After.

The full description is OpenAPI 3.1: /v1/openapi.json.

What an app may do

books:read · Read your books: Invoices, customers, spending, bills, suppliers and the totals on your home page.
books:propose · Suggest changes for you to approve: Expenses, bills, payments and reminders wait on “For you to check” until you approve them.

There is no scope that changes the books directly. Writing straight to the books, and webhooks, are planned.