openapi: 3.0.3
info:
  title: Fortnox REST API (Representative Subset) Accounts API
  description: 'Grounded OpenAPI description of the Fortnox REST API - the Swedish cloud accounting/ERP platform for SMBs and accounting bureaus. Base URL is https://api.fortnox.se/3/. Authentication is OAuth2 Authorization Code Flow: each request carries the Access-Token (Bearer JWT, 1h) header plus the Client-Secret header issued to your Fortnox app. The old fixed Access-Token/Client-Secret integration keys were deprecated 2025-04-30.


    SCOPE / FIDELITY NOTE: The Fortnox API exposes 40+ resources. This document ships a solid, representative SUBSET (Invoices, Customers, Articles, Orders, Offers, Vouchers, Accounts, Financial Years, Suppliers, Supplier Invoices, Projects) with pragmatic, partial field-level schemas. Paths, methods, identifiers, the wrapper-object response envelope (e.g. { "Invoice": {...} }, { "Invoices": [...] }), and auth are grounded in Fortnox''s developer documentation. Per-field property coverage is intentionally partial and MODELED/summarized from the docs, not transcribed field-for-field for every resource. Verify exact field sets and validation against https://api.fortnox.se/apidocs before production use.'
  version: '3.0'
  contact:
    name: Fortnox Developer
    url: https://www.fortnox.se/developer
  license:
    name: Fortnox API License / Terms
    url: https://www.fortnox.se/developer
servers:
- url: https://api.fortnox.se/3
  description: Fortnox REST API v3
security:
- accessToken: []
  clientSecret: []
tags:
- name: Accounts
  description: Chart of accounts.
paths:
  /accounts:
    get:
      operationId: listAccounts
      tags:
      - Accounts
      summary: List accounts
      parameters:
      - name: financialyear
        in: query
        schema:
          type: integer
      responses:
        '200':
          description: A list of accounts.
          content:
            application/json:
              schema:
                type: object
                properties:
                  Accounts:
                    type: array
                    items:
                      $ref: '#/components/schemas/Account'
                  MetaInformation:
                    $ref: '#/components/schemas/MetaInformation'
    post:
      operationId: createAccount
      tags:
      - Accounts
      summary: Create an account
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                Account:
                  $ref: '#/components/schemas/Account'
      responses:
        '201':
          $ref: '#/components/responses/AccountResponse'
  /accounts/{Number}:
    parameters:
    - name: Number
      in: path
      required: true
      schema:
        type: integer
    - name: financialyear
      in: query
      schema:
        type: integer
    get:
      operationId: getAccount
      tags:
      - Accounts
      summary: Retrieve an account
      responses:
        '200':
          $ref: '#/components/responses/AccountResponse'
    put:
      operationId: updateAccount
      tags:
      - Accounts
      summary: Update an account
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                Account:
                  $ref: '#/components/schemas/Account'
      responses:
        '200':
          $ref: '#/components/responses/AccountResponse'
components:
  responses:
    AccountResponse:
      description: A single account.
      content:
        application/json:
          schema:
            type: object
            properties:
              Account:
                $ref: '#/components/schemas/Account'
  schemas:
    Account:
      type: object
      description: An account in the chart of accounts.
      properties:
        Number:
          type: integer
        Description:
          type: string
        Active:
          type: boolean
        VATCode:
          type: string
        Year:
          type: integer
        BalanceBroughtForward:
          type: number
      required:
      - Number
      - Description
    MetaInformation:
      type: object
      description: Pagination metadata returned on list endpoints.
      properties:
        '@TotalResources':
          type: integer
        '@TotalPages':
          type: integer
        '@CurrentPage':
          type: integer
  securitySchemes:
    accessToken:
      type: apiKey
      in: header
      name: Access-Token
      description: OAuth2 Access-Token (Bearer JWT, valid 1 hour) obtained via the Authorization Code Flow from https://apps.fortnox.se/oauth-v1/token. Sent in the Access-Token header on every request.
    clientSecret:
      type: apiKey
      in: header
      name: Client-Secret
      description: The Client-Secret issued to your registered Fortnox developer application. Sent in the Client-Secret header alongside the Access-Token on every request.