First-party app
Fortnox

Fortnox

Manage customers, suppliers, articles, invoices, orders, offers, supplier invoices, vouchers, accounts, projects and payments in Fortnox, the Swedish cloud accounting and ERP platform.

stable Finance & AccountingProductivity

About

Fortnox ships in the w6w first-party pack. It declares 54 actions, 2 health checks, and the host runs its code in a sandbox that never sees the credential.

App id
io.w6w.fortnox
Version
0.1.0
Author
w6w
Licence
MIT
Categories
Finance & Accounting · Productivity

Overview

Fortnox is the most widely used cloud accounting, invoicing and ERP platform for small and medium businesses in Sweden. This app covers Fortnox’s REST API v3 (api.fortnox.se) for the core accounting objects: customers, suppliers, articles, customer invoices (create, update, book, cancel, credit, email), orders, offers, supplier invoices, vouchers and voucher series, the chart of accounts, invoice payments, projects, cost centers, financial years and the connected company.

Every path, verb, query parameter, body field and enum was read on 2026-10-06 from Fortnox’s own OpenAPI 3.0.3 document (embedded in the Redoc page at api.fortnox.se/apidocs) and the developer guides at fortnox.se/developer, plus a live check of the Statuspage at status.fortnox.se.

Three details are easy to get wrong: bodies and responses are wrapped in a resource key ({"Customer": {...}}, lists as {"Customers": [...], "MetaInformation": {...}}); refresh tokens rotate, so every refresh invalidates the previous one; and OAuth scopes are per resource (customer, invoice, bookkeeping, …), each granting read and write, with access_type=offline required to receive a refresh token.

Build with Fortnox

Three routes to the same 54 actions. The Workflow tab is generated from Fortnox's own manifest and carries its real ids, so it is copy-pasteable; the Code and CLI examples are the same call for any action on any app, so every app-specific value in them is a blank you fill in.

Create Account

account-create

Create a ledger account.

Get Account

account-get

Fetch one ledger account by number.

List Accounts

account-list

List ledger accounts sorted by number.

Update Account

account-update

Update a ledger account. Only the properties sent are changed; the number itself cannot be changed.

Create Article

article-create

Create an article. Only the description is required.

Delete Article

article-delete

Delete an article by article number.

Get Article

article-get

Fetch one article by article number.

List Articles

article-list

List articles sorted by article number.

Update Article

article-update

Update an article. Only the properties sent are changed.

Get Company Information

company-information-get

Fetch the connected company: name, organisation number, address and database number.

List Cost Centers

cost-center-list

List cost centers.

Create Customer

customer-create

Create a customer. Only the name is required.

Delete Customer

customer-delete

Delete a customer. Fortnox reserves the number even after deletion.

Get Customer

customer-get

Fetch one customer by customer number.

List Customers

customer-list

List customers sorted by customer number, with Fortnox's own filters.

Update Customer

customer-update

Update a customer. Only the properties sent are changed; the rest are left as they are.

Get Financial Year

financial-year-get

Fetch one financial year by its numeric id.

List Financial Years

financial-year-list

List the company's financial years; filter to the one containing a date.

Bookkeep Invoice

invoice-bookkeep

Book the invoice into the ledger (creates a voucher).

Cancel Invoice

invoice-cancel

Cancel an invoice.

Create Invoice

invoice-create

Create a customer invoice. Fortnox fills omitted fields from the company's predefined values.

Credit Invoice

invoice-credit

Create a credit invoice for this invoice; it is referenced in CreditInvoiceReference.

Get Invoice

invoice-get

Fetch one invoice, with its rows, by document number.

List Invoices

invoice-list

List customer invoices with Fortnox's own filters (status, dates, customer, project, OCR).

Create Invoice Payment

invoice-payment-create

Register a payment against a customer invoice.

List Invoice Payments

invoice-payment-list

List payments registered against customer invoices.

Send Invoice By Email

invoice-send-email

Email the invoice to the customer. Fortnox exposes this as a GET that has a side effect.

Update Invoice

invoice-update

Update an unbooked invoice. Only the properties sent are changed; see the rows note.

Get Current User

me-get

Fetch the Fortnox user the access token belongs to (needs the profile scope).

Create Offer

offer-create

Create an offer (quote).

Create Order From Offer

offer-create-order

Turn an offer into an order.

Get Offer

offer-get

Fetch one offer, with its rows, by document number.

List Offers

offer-list

List offers (quotes) with Fortnox's own filters.

Update Offer

offer-update

Update an offer. Only the properties sent are changed; see the rows note.

Create Order

order-create

Create an order.

Create Invoice From Order

order-create-invoice

Turn an order into a customer invoice.

Get Order

order-get

Fetch one order, with its rows, by document number.

List Orders

order-list

List orders with Fortnox's own filters.

Update Order

order-update

Update an order. Only the properties sent are changed; see the rows note.

Create Project

project-create

Create a project. Only the description is required.

Get Project

project-get

Fetch one project by project number.

List Projects

project-list

List projects.

Create Supplier

supplier-create

Create a supplier. Only the name is required.

Get Supplier

supplier-get

Fetch one supplier by supplier number.

Bookkeep Supplier Invoice

supplier-invoice-bookkeep

Book the supplier invoice into the ledger.

Create Supplier Invoice

supplier-invoice-create

Register a supplier invoice.

Get Supplier Invoice

supplier-invoice-get

Fetch one supplier invoice by its Fortnox-given number.

List Supplier Invoices

supplier-invoice-list

List supplier invoices with Fortnox's own filters.

List Suppliers

supplier-list

List suppliers sorted by supplier number.

Update Supplier

supplier-update

Update a supplier. Only the properties sent are changed.

Create Voucher

voucher-create

Create a manual voucher.

Get Voucher

voucher-get

Fetch one voucher by series and number. The same series and number repeat every year, so pass the financial year id.

List Vouchers

voucher-list

List vouchers (ledger entries) in a financial year.

List Voucher Series

voucher-series-list

List the voucher series (code, description, next number).

A workflow step names the app and the action, and the editor fills in the connection when you pick one. This is the Step shape from the workflow spec, carrying Fortnox's real ids.

{
  "manifestVersion": "2",
  "name": "fortnox-example",
  "steps": [
    {
      "id": "account-create",
      "uses": {
        "app": "io.w6w.fortnox",
        "action": "account-create",
        "connection": "conn_YOUR_CONNECTION_ID"
      },
      "with": {
        "number": "<number>"
      }
    }
  ]
}

Here are some of the things you can do

  • Create Account

    perform
    account-create
  • Get Account

    read
    account-get
  • List Accounts

    search
    account-list
  • Update Account

    perform
    account-update
  • Create Article

    perform
    article-create

+49 more actions available

Every app-specific value here is a blank you have to fill in. An app action is reached through the connection that authenticates it, so the address is a connection id, not the app id — and connections belong to your account, so a public page cannot know yours. Create one for Fortnox, then fill in the three blanks: conn_YOUR_CONNECTION_ID, the action key, and the parameters that action declares. The call itself is real — the shape is transcribed from the studio's own snippet builder, which prints the same kind of blanks — but nothing in it is specific to Fortnox. The Workflow tab is where this app's real ids are.

Install
npm install @w6w/sdk
yarn add @w6w/sdk
pnpm add @w6w/sdk
deno add npm:@w6w/sdk
Code
import { W6wClient, isActionRun } from "@w6w/sdk";

// Reads W6W_BASE_URL and W6W_TOKEN from the environment when omitted.
const client = new W6wClient();

const envelope = await client.run({
  urn: "conn_YOUR_CONNECTION_ID",
  action: "account-create",
  payload: {
    number: "<value>",
    // description: "<value>",
    // active: "<value>",
    // sru: "<value>",
    // costCenterSettings: "<value>",
    // projectSettings: "<value>",
    // vatCode: "<value>",
    // additionalFields: "<value>",
    // financialYear: "<value>",
  },
});

if (isActionRun(envelope)) console.log(envelope.value);
Install the CLI
npm install -g @w6w/cli
CLI
w6w run conn_YOUR_CONNECTION_ID --action account-create --payload '{"number":"<value>"}'

Give an AI agent Fortnox — without giving it Fortnox's credentials. One MCP endpoint exposes every app, function and workflow the caller is entitled to, as tools it can discover and run. Access is granted per team while we onboard.

One tool call
{
  "name": "w6w_invoke",
  "arguments": {
    "ref": "app:io.w6w.fortnox#account-create",
    "input": {
      "number": "<number>"
    }
  }
}

Every tool names its target with a single ref. The app: form above doesn't name a connection at all — the host resolves which of the caller's Fortnox connections to sign with, and refuses rather than guesses when the answer is ambiguous.

What the agent gets

Credentials it can't read

The token is attached host-side, at the moment of the call. It is never a tool argument, never in the model's context, and never in a transcript — so a prompt injection has nothing to exfiltrate.

A tool surface scoped to the caller

Tools are derived per end user from what that person has actually connected and is entitled to — not one shared bot identity carrying the union of everyone's access.

A durable workflow in one call

Multi-step work runs on the workflow engine and returns a run handle the agent can poll — retries, branching and state survive the conversation that started them.

Health-aware discovery

Fortnox's declared health checks are on the surface too, so an agent can tell "the vendor is down" from "your credential expired" before it burns a retry on either.

The MCP surface is part of the hosted platform. Fortnox itself is MIT, and the runtime that executes it is source-available (FSL).

Request MCP access

Health checks

Fortnox declares its own checks, so its health is a property of the app rather than something the host guesses at.

service

Fortnox API status

Status of the `Fortnox API` and `Fortnox ID` (login) components on Fortnox's Atlassian Statuspage (status.fortnox.se). Other components on the page are unrelated to the API and are ignored.

quota

API rate-limit headroom