A hosted Fortnox MCP server you activate in Fortnox

What is a Fortnox MCP server?

A Fortnox MCP server exposes the Fortnox accounting API over the Model Context Protocol (MCP) — an open standard — so AI clients such as Claude, ChatGPT, and Cursor can read and write your Fortnox account, limited to the permissions you approve at activation.

Anthropic launched MCP in late 2024 to solve a recurring problem: every AI client used to need a custom integration for every external service. With MCP, one server per service is enough, and any MCP client can connect to it and use the same tools. Fortnox has no MCP layer of its own — Nordsynk is the bridge, putting the full compiled OpenAPI surface (233 paths, 377 operations for invoices, customers, suppliers, and bookkeeping) behind a single MCP server.

The connection has two layers. A general layer (codemode) lets your AI client search and call any Fortnox endpoint across the full API surface — codemode.grep finds the right operation, codemode.request calls it. A second layer (ready-made skills) covers Fortnox workflows that aren't plain API calls, like OCR interpretation of supplier invoices and SIE export — skills.grep finds the right guide, skills.invoke runs the reviewed workflow. Reads happen freely within the account's permissions; writes — anything that creates or changes data in Fortnox — always wait for your approval before they execute.

Get started in 5 minutes

A Fortnox administrator activates Nordsynk in the Fortnox portal once. Each user then connects from their AI client, signs in to Nordsynk, and approves their companies. Fortnox OAuth is used separately to connect or reconnect each company.

What can you do?

Nordsynk turns Fortnox workflows into tasks you handle in the chat, not a list of technical tool names. The list below is a sample — the full API layer covers more workflows than fit here. A few examples:

Ask about something that isn't listed here and the AI client still finds the right operation on its own: the full compiled Fortnox API surface — 233 paths, 377 operations — is searchable through codemode.

Hosted vs open source vs Zapier

Nordsynk, a self-hosted open-source server, and Zapier MCP all solve the same underlying problem — connecting an AI client to Fortnox — but with different trade-offs between control, maintenance, and coverage. The difference shows up most clearly in Swedish accounting workflows — OCR, approvals, and SIE — which aren't part of Fortnox's general API and require either your own implementation or a provider that has already built them. The table is a quick overview; the full comparisons are linked below.

Nordsynk fits you if you want to be running without thinking about hosting, with write approvals and Swedish workflows like OCR and invoice approval built in. A self-hosted open-source server fits you if you already have the infrastructure and want to own the whole stack. Zapier MCP fits you if you already run Fortnox through Zaps and want to add an AI client to the same ecosystem.

Switching between the options doesn't change your bookkeeping in Fortnox — the MCP layer is just a way to reach the same data, so you can try Nordsynk without risking anything.

Already a Zapier customer and curious about the difference? Read the full comparison: Nordsynk vs Zapier MCP for Fortnox.

Thinking about running your own server? See what you take on: Nordsynk vs a self-hosted open-source Fortnox MCP server.

Security and control

AI clients authenticate to Nordsynk and receive only the companies explicitly approved for that client. Fortnox data access still uses per-user, per-company OAuth tokens and remains limited by Fortnox permissions, product licenses, Nordsynk seats, and approved integration scopes.

Writes — anything that creates, changes, or deletes data in Fortnox — never go through directly. The AI client queues a write proposal, and you approve or decline the exact stored proposal through a link. There is no way to edit the fields on the approval screen: if something is wrong, you decline, optionally with a comment on what needs to change, and the client prepares a new proposal from scratch.

Every call is logged with user, timestamp, and action, and every approval decision is saved to its own history. Access is checked per company at runtime: a company without the user's active Nordsynk seat or usable Fortnox authorization is denied without disconnecting the other approved companies.

If Nordsynk adds new Fortnox permissions in a later version, you'll reconnect each affected company from Nordsynk and approve the new Fortnox permissions there. The AI-client connector can stay connected.

Pricing: 199 SEK per Fortnox company and user per month

Nordsynk costs 199 SEK per Fortnox company and user per month, billed through Fortnox Marketplace alongside the rest of your Fortnox subscription.

The license applies per Fortnox company. If a user works across several companies, they need their own seat in each one — a Marketplace seat in one company does not grant access in the others. Accounting firms managing multiple client companies count seats per company, not per employee.

There is no separate Nordsynk invoice and no credit card on file with Nordsynk — the purchase and payment happen entirely inside Fortnox, just like your other Fortnox add-ons.

The Fortnox administrator assigns and removes seats directly in the Fortnox portal. The next time that person signs in through their AI client, access is up to date.

Full terms and what's included are on Nordsynk's pricing page.

Frequently asked questions about Fortnox MCP