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ERP and accounting

Connect Fortnox to Hypamoon

Possible, with help from Fortnox. The API is documented, but you cannot just create a key: access goes through Fortnox first.

Possible

The check

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

Public API docs
Yes. Public developer portal with guides and an API reference at apps.fortnox.se/apidocs. Read the docs
A key you create yourself
No. Building an integration needs a developer license that Fortnox adds to your account; you then create the integration in the Developer Portal, where it can stay hidden for private use. fortnox.se
Versions or a changelog
Yes. Change policy with fixed notice periods per release type, for example three months before a major version, announced on the developer blog. fortnox.se
How it signs in
OAuth 2.0: the customer approves the integration once, after which you get access tokens that last an hour, with a refresh token or with client credentials plus the customer's tenant ID.
Webhooks
No. fortnox.se
Hosting
Cloud
Condition
Needs a Fortnox developer license, added to your account by Fortnox.

In practice

What it takes in a real Fortnox administration.

Getting access
You register as a Fortnox integration developer and get a developer license from Fortnox, create the integration with its scopes in the Developer Portal, and the Fortnox customer approves it once.
Limits
300 requests per minute per client ID and tenant, measured as 25 requests per 5 seconds; above that the API answers 429. fortnox.se
Writing
Read and write. Create and update invoices and customers, and create vouchers, within the scopes the customer approved.
Cost
Not published.

Your own customer portal on Fortnox, with invoices and orders in one place.

  • Customers, invoices, orders, articles and vouchers, from the scopes you approve.
  • AI that checks new supplier invoices and flags customers who start paying late, with you approving every change.
  • A portal for your customers and a short weekly email for you.

Ask your chat

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

  • Which customer invoices are more than 30 days overdue?
  • Which articles sold less this quarter than last quarter?

On a schedule

Fortnox has no webhooks, so an agent checks every 15 minutes and decides what happens next.

  1. Every 15 minutes

    New orders from your own web form that are not in Fortnox yet.

    AI decides

    AI checks the customer, the articles and the prices and flags anything odd.

    Then

    An order is created in Fortnox.

    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 Fortnox data.

  • For your customers

    Customers sign in and see their own invoices and orders, straight from Fortnox.

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 invoices that passed their due date.

Fortnox 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 Fortnox waits for your approval, one call at a time. How adapters work

Good to know

  • Fortnox signs in with OAuth or signed requests only, with tokens that expire. The Hypamoon vault holds a fixed key today, so an adapter for Fortnox takes more work: ask your chat to check this first.
  • Fortnox sends change events over a WebSocket stream, not HTTP webhooks. Access tokens expire after an hour, so an adapter has to renew them.

Try it in your chat

First get access from Fortnox. Then fill in what to read and write, and send it.

Say this in your chat

Build the Hypamoon recipe build-an-adapter for Fortnox. API docs: https://apps.fortnox.se/apidocs. 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.

Fortnox 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 Fortnox. 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 Fortnox?

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

Start free

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