Fortnox
Fortnox is a Swedish cloud accounting, ERP, and business-administration platform for small and medium-sized businesses and accounting bureaus. Its REST API at https://api.fortnox.se/3/ programmatically manages accounting and financial data - invoices, customers, articles, orders, offers, vouchers, accounts, suppliers, supplier invoices, projects, and financial years - authenticated with OAuth2 Authorization Code Flow. Fortnox also publishes a duplex WebSocket event stream at wss://ws.fortnox.se/topics-v1 that pushes minimal change notifications across domains so integrations can react to changes instead of polling.
Fortnox publishes 12 APIs on the APIs.io network, including Topics WebSocket API, Accounts API, Articles API, and 9 more. Tagged areas include Accounting, ERP, Invoicing, Bookkeeping, and Sweden.
The Fortnox catalog on APIs.io includes 1 event-driven AsyncAPI specification and 1 Spectral governance ruleset.
Fortnox’s developer surface includes authentication, documentation, engineering blog, and 7 more developer resources.
Kin Score
APIs 12
Individual APIs this provider publishes, each with its own machine-readable definition.
Fortnox Topics WebSocket API
Duplex WebSocket stream at wss://ws.fortnox.se/topics-v1 that pushes minimal change-notification events across domains (invoices, supplier-invoices, customers, articles, orders,...
Fortnox Accounts API
Chart of accounts.
Fortnox Articles API
Article (product/service) register.
Fortnox Customers API
Customer register.
Fortnox Financial Years API
Financial (accounting) years.
Fortnox Invoices API
Accounts-receivable customer invoices.
Fortnox Offers API
Offers (quotations).
Fortnox Orders API
Sales orders.
Fortnox Projects API
Projects for tagging and reporting.
Fortnox Supplier Invoices API
Inbound accounts-payable supplier invoices.
Fortnox Suppliers API
Supplier register.
Fortnox Vouchers API
Accounting vouchers (journal entries).
Scroll for all 12
Open Collections 13
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
API Collection
OPEN COLLECTIONFortnox REST API (Representative Subset) Accounts API
OPEN COLLECTIONFortnox REST API (Representative Subset) Accounts Offers API
OPEN COLLECTIONFortnox REST API (Representative Subset) Accounts Orders API
OPEN COLLECTIONFortnox REST API
OPEN COLLECTIONScroll for all 13
Pricing Plans 1
Published pricing tiers and plan structures.
Rate Limits 1
Documented rate limits and quota policies.
Fortnox Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals for API financial operations.
Fortnox Finops
FINOPSEvent Specifications 1
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Fortnox Topics WebSocket API
AsyncAPI 2.6 description of Fortnox's **real duplex WebSocket API** at `wss://ws.fortnox.se/topics-v1` (the "Topics" service). Unlike the REST API at https://api.fortnox.se/3/, ...
ASYNCAPISpectral Rules 1
Spectral governance rulesets for linting and validating these APIs.
Fortnox API Rules
SPECTRALSecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
Recommended x-agentic-access execution contracts for AI agents.
Resources
Documentation 1
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Access & Security 2
Authentication, authorization, and security posture
Operate 1
Status, limits, changes, and where to get help
Commercial 2
Pricing, plans, and the legal terms of use
Company 3
The organization behind the API
Source (apis.yml)
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