Skip to content
Hypamoon
Works in Claude, ChatGPT and Copilot Start free

ERP and accounting

Connect Billy to Hypamoon

Yes. Billy has a public, versioned API and you create the key yourself, so your chat can write the adapter.

Open

The check

Three questions about the API of Billy, answered from its own docs.

Public API docs
Yes. Read the docs
A key you create yourself
Yes. Create an access token under Settings, Access tokens; each token belongs to one company and does not expire. billy.dk
Versions or a changelog
Yes. The version is in the base URL (v2), and Billy offers an email list for API changes. billy.dk
How it signs in
An access token from Settings, Access tokens, sent in the X-Access-Token header; one token per company.
Webhooks
Not confirmed.
Hosting
Cloud

In practice

What it takes in a real Billy administration.

Getting access
Log in to Billy, go to Settings, Access tokens, create a token and copy it.
Limits
None published.
Writing
Read and write. Resources can be listed, read, created, updated and deleted where the resource allows it, for example invoices, contacts and bills.
Cost
Not published.

Your own invoice and bookkeeping tools on Billy, shaped around your daily work.

  • Contacts, invoices, bills, products and bank lines, straight from Billy.
  • AI that proposes accounts for new bills and spots customers who pay later than usual, with you approving every booking.
  • A screen for your team and a short weekly email for you.

Ask your chat

Answers straight from your Billy data, in Claude or another chat with the full Hypamoon connection.

  • Which invoices are still unpaid after their due date?
  • How much did we spend with each supplier this quarter?

On a schedule

Billy has no webhooks we could confirm, so an agent checks every 15 minutes and decides what happens next.

  1. Every 15 minutes

    New bills in Billy that are not booked yet.

    AI decides

    AI looks at earlier bills from the same supplier and proposes the account and VAT code.

    Then

    The proposal is saved on the bill in Billy after you approve it.

    AI proposes, you approve

A screen for your team or customers

An app on your own address, with sign-in, on top of the same Billy data.

  • For your team

    Your team sees open invoices per customer and what came in this week.

Add Hypamoon

Text messages, email, phone, payments and agents run in the same project as the adapter.

  • Agent on a schedule

    Once a week, an agent emails you the customers who pay later than they used to.

Billy stays the core: your chat builds the rest on its API, as an adapter plus an app and agents in your Hypamoon project. Reading starts after you click Allow in the portal. Every change an agent or a chat makes in Billy waits for your approval, one call at a time. How adapters work

Good to know

  • Your adapter uses a fixed key: you paste it once in the Hypamoon portal, never in the chat, and it only goes to the API host you allow.
  • Tokens are tied to one company, so with several companies you create one token per company. HTTP Basic auth with email and password is also possible, but a token is the safer choice.

Try it in your chat

Fill in what to read and write, and send it.

Say this in your chat

Build the Hypamoon recipe build-an-adapter for Billy. API docs: https://www.billy.dk/api/. Read: [what]. Write: [what, or nothing].

Open in Claude

In Claude, or another chat with the full Hypamoon connection; adapters are not in ChatGPT yet. You paste the key in the portal, never in the chat. The full recipe

Sources

Checked on 7 November 2026.

Billy is a name of its owner, used here only to describe the software. This page is not an official integration and Hypamoon has no partnership with Billy. Found something that changed? Tell us at support.

More in erp and accounting

All 1094 tools

Tool not listed? Ask the chat to check its API.

The same three checks work for any software. Your chat reads the vendor's own docs and tells you what it found.

Say this in your chat

Check if [software] has an open API that a Hypamoon adapter can use: public API docs, a key or token I can create myself without asking the vendor, and versions or a changelog. Link the pages you used.

Open in Claude Open in ChatGPT

Fill in the name of your software. Checking needs no connection to Hypamoon.

Ready to connect Billy?

Connect your chat once, then ask it to build the adapter.

Start free

Works in Claude, ChatGPT and Copilot. Add to Claude Add to ChatGPT Add to Copilot