Fortnox MCPFortnox MCP server
you activate in Fortnox
Nordsynk is a hosted Fortnox MCP server. You activate it in Fortnox, add one address to Claude, ChatGPT, or Cursor, and then ask your books questions in plain language.
Nordsynk runs the server for you. There is nothing to install or host.
Example · invented invoices
Which supplier invoices are unpaid and due before 31 October?
Nordsynk reads Fortnox
Supplier invoices · unpaid · due until 2026-10-31
Three invoices are unpaid and due before 31 October:
- Kvarnen AB15 Oct12,500.00 SEK
- Nordlys Frakt AB21 Oct4,280.00 SEK
- Strand Revision AB30 Oct9,750.00 SEK
What is a Fortnox MCP server?
MCP, the Model Context Protocol, is an open standard that lets an AI assistant such as Claude, ChatGPT, or Cursor use tools in other services. Anthropic introduced it in late 2024. A Fortnox MCP server is the connection that lets the assistant read in your Fortnox.
The Fortnox API has no MCP layer of its own. Nordsynk is the bridge: a hosted server that gives the assistant the whole Fortnox API, 377 operations, and ready-made workflows for things that are not plain API calls, such as reading supplier invoices, approvals, and SIE export.
The assistant signs in as you. It reaches only the companies you have approved, and only what your own Fortnox user has permission to do.
AI assistant
Claude, ChatGPT, Cursor
You ask in plain language
MCP server
Nordsynk
Sign-in and company choice
Bookkeeping
Fortnox
Your company, your permissions
Changes
Open as a preview in your browser that you approve or decline.
You see the change before it is made
Asking is immediate. When you ask the assistant to change something in Fortnox, such as creating a customer invoice, Nordsynk opens a preview in your browser. It shows the company, the action, and what will be created.
Nothing changes in Fortnox until you approve it.
The proposal cannot be edited on the page. If something is wrong, you decline it or request a change, and the assistant prepares a new proposal.
Example · invented invoice
Create a customer invoice for Björk & Co for 12,500 SEK for consulting hours in September.
I have prepared the invoice. Open the preview and approve it to create it in Fortnox.
Bookkeeping change
Awaiting approvalApprove this Fortnox change?
Review what Nordsynk is about to do in Fortnox before you approve it.
What will happen
Creates a customer invoice for Björk & Co for 12,500.00 SEK excluding VAT.
- Company
- Acme AB
- Action
- Create customer invoice
- Consulting hours, 10 h × 1,250.00 SEK12,500.00 SEK
Activate, paste the address, connect
A Fortnox administrator activates Nordsynk in the Fortnox portal once. After that, each user adds Nordsynk to their AI assistant, signs in, and chooses which companies the assistant may use.
Simplified picture · invented companies
Activate in Fortnox
Fortnox portal · Manage integrations
The administrator assigns seats to users.
Paste the address
AI assistant · Add custom connection
Name
Nordsynk
MCP server address
https://mcp.nordsynk.se/mcp
Sign in and choose companies
Nordsynk · Choose companies for your AI assistant
- Acme AB
- Björk & Co AB
- Strand Revision AB
Video guide · 4:07
Connect Claude to Fortnox – step by step
Narrated in Swedish with English subtitles. The video plays from YouTube when you click.
Video guide · 3:29
Connect ChatGPT to Fortnox – step by step
Narrated in Swedish with English subtitles. The video plays from YouTube when you click.
Claude Desktop
For you if the app is installed and you want Fortnox available every time you open it.
- 01Open Customize → Connectors and choose Add custom connector.
- 02Paste the MCP server address (see below).
- 03Click Connect, sign in to Nordsynk, and approve the companies Claude may use.
Claude.ai and Claude Team
For an accounting firm or finance team that runs Claude in the browser and does not want to install anything.
- 01Go to claude.ai → Customize → Connectors and choose Add custom connector.
- 02Paste the address. Everyone on the team adds the connection themselves.
- 03Sign in to Nordsynk and approve the companies Claude may use.
ChatGPT
The menu options depend on your plan and workspace. A custom MCP server is available on ChatGPT Pro (read and search only) and on Business and Enterprise/Edu (read and make changes). In a workspace, the admin controls who may add one. OpenAI does not document Free or Plus. If you do not see the option, check your plan and role.
- 01Open Customize → Plugins, click Add, and choose Create custom MCP server.
- 02Enter the address as the Server URL and keep OAuth as the authentication.
- 03Sign in to Nordsynk and approve the companies. The first time, ChatGPT asks whether it may use Nordsynk: choose Allow once or Always allow.
Cursor
For you if you want to ask about Fortnox without leaving the editor.
- 01Open Cursor's MCP settings.
- 02Add the address as a remote server (streamable HTTP).
- 03Sign in to Nordsynk and approve the companies Cursor may use the first time it connects.
Use the address on top. If your client requires SSE, use the address on the second line. The client discovers the sign-in on its own, so there are no credentials to fill in.
What can you do with Nordsynk?
Nordsynk turns Fortnox workflows into tasks you solve in the chat. This is a selection, and the questions are examples of how you can phrase them.
Search the ledger
Ask for vouchers, accounts, or amounts. Nordsynk filters by account, date, and free text.
› Show all voucher rows on account 4010 in March.
Customer invoices
Create, post, and email an invoice in the same conversation, or find the unpaid ones. The invoice is sent with Fortnox's own email.
› Show unpaid customer invoices over 10,000 SEK that fell due in June.
Supplier invoices
Read the inbox, interpret scanned documents, and run the approval flow. Approval follows the same rules as in Fortnox.
› Show supplier invoices over 5,000 SEK awaiting approval.
SIE export
Get a SIE file for the right financial year, ready for the auditor or another system.
› Export SIE for the 2025 financial year.
Vouchers and chart of accounts
Look up accounts and trace a posting without opening Fortnox. The chart of accounts is the company's own.
› Which account was the April advertising cost posted to?
Reports
Income statements, balance sheets, and turnover, fetched straight from Fortnox rather than from an old export.
› What was Q1 revenue compared with the same period last year?
Document archive
Upload a file and attach it to the right voucher, and it lands in the Fortnox document archive.
› Attach this receipt image to voucher 245.
And the rest of Fortnox
If you ask about something not listed here, the assistant finds the right operation itself among Fortnox's 377 operations.
Hosted server, your own server, or Zapier?
Nordsynk, a self-hosted open-source server, and Zapier MCP solve the same problem but weigh control, maintenance, and coverage differently. The open-source and Zapier columns describe the typical case and vary by project and plan. The dated comparisons below go through the sources.
- Hosting
- NordsynkHosted by Nordsynk
- Open sourceYou host and maintain the server yourself
- Zapier MCPHosted by Zapier
- API coverage
- NordsynkThe full Fortnox API plus Swedish accounting workflows (OCR, approvals, SIE)
- Open sourceDepends on the project — usually a subset of endpoints
- Zapier MCPThe actions Zapier exposes for Fortnox
- Activation
- NordsynkIn the Fortnox portal, with Fortnox's own sign-in
- Open sourceYou register your own Fortnox integration and handle sign-in yourself
- Zapier MCPA Zapier account connected to Fortnox
- Approval before a change
- NordsynkBrowser preview by default. A company can choose auto-approval.
- Open sourceDepends on the implementation — no built-in approval step by default
- Zapier MCPThe AI client asks you to approve the first run. A preview of the Fortnox change itself is not described.
- Price
- Nordsynk199 SEK per Fortnox company and user per month, on your Fortnox invoice
- Open sourceFree code — you cover hosting cost and time
- Zapier MCPA Zapier subscription plus task-based usage
Nordsynk fits you if you want to be running without thinking about hosting, with approval before every change 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 assistant to the same ecosystem.
Security and control
You sign in as yourself
The assistant gets only the companies you have approved, and only what your Fortnox user has permission to do, within the Fortnox areas the company's access policy allows. Fortnox permissions and product licences always apply.
Everything can be followed up
Every call is logged with user, time, and action, and every approval is saved in its own history.
One company at a time
If you lack a seat or a valid Fortnox connection in one company, only that company is denied. The other companies are unaffected.
199 SEK per Fortnox company per user per month
You buy Nordsynk through Fortnox and pay on your Fortnox invoice. The licence applies per Fortnox company, so a user who works in three companies needs a seat in each of them.
The Fortnox administrator assigns and removes seats in the Fortnox portal. Accounting firms can instead sign a Nordsynk agreement priced per active client company.
Example · one user, three companies
Anna works in three companies
- Anna · Acme AB199.00 SEK
- Anna · Björk & Co AB199.00 SEK
- Anna · Strand Revision AB199.00 SEK
Frequently asked questions about Fortnox MCP
What is a Fortnox MCP server?
A Fortnox MCP server connects an AI assistant such as Claude, ChatGPT, or Cursor to Fortnox through the Model Context Protocol. The assistant can then read your books and prepare changes from plain questions. Nordsynk is a hosted Fortnox MCP server: you activate it in Fortnox and add one address to your assistant.
Does Fortnox have its own MCP support?
No. The Fortnox API has no MCP layer of its own. Nordsynk is the hosted bridge that makes the Fortnox API available over MCP, so Claude, ChatGPT, and Cursor can connect without Fortnox building the support.
Do I need to host the MCP server myself?
No. Nordsynk runs the server as a hosted service. You activate in the Fortnox portal and paste one address into your AI assistant. No terminal or infrastructure work is needed.
Which AI assistants work with Nordsynk?
Claude (Desktop and claude.ai), ChatGPT, and Cursor, plus other clients that support remote MCP with sign-in. The same address is used in all of them. In ChatGPT, your plan and workspace decide whether Create custom MCP server is available: open Customize → Plugins and check the Add menu.
Can the AI assistant change Fortnox without me knowing?
Not by default. Every change opens a preview in your browser where you approve, decline, or request a change. A company can choose auto-approval itself, and changes then run immediately. Fortnox permissions and the company's access policy in Nordsynk apply in both modes.
What does a Fortnox MCP server from Nordsynk cost?
199 SEK per Fortnox company per user per month, on your Fortnox invoice. The licence applies per company: a user in three companies needs three seats.
Can I use Nordsynk in several companies?
Yes. One connection can cover several companies, and you choose which when you sign in. The Fortnox connection and the Nordsynk seat are per company, though, and you need a seat in each company where you use Nordsynk.
How does Nordsynk differ from Zapier MCP or a self-hosted open-source server?
Zapier MCP builds on Zapier's actions and plans with task-based metering. A self-hosted open-source server gives you full control, but you host it, maintain it, and handle sign-in yourself. Nordsynk is hosted and gives access to the whole Fortnox API (377 operations) plus ready-made workflows for supplier invoices and SIE, among others.
Does Fortnox have an API?
Yes. Nordsynk's current compiled Fortnox OpenAPI surface includes 233 paths and 377 operations for invoices, customers, suppliers, bookkeeping, projects, and more. Nordsynk makes that surface available over MCP so your AI assistant can use it directly.
Connect Claude or ChatGPT to Fortnox
Activate Nordsynk in the Fortnox portal. It takes under a minute.