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.
Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.
API Evangelist profiles Fortnox the way a machine reads it — 21 machine-readable artifacts across 12 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Fortnox scores 43.9/100 (thin), with a separate agent-readiness read of 54/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Fortnox
Each block below is one kind of artifact we hold for Fortnox. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 12
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
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 within the panel for all 12 ·
Open Collections 1
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Fortnox REST API
OPEN COLLECTIONPricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Fortnox Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Fortnox Finops
FINOPSEvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
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
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
Fortnox API Rules
SPECTRALSecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Fortnox — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
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
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