Firely
Firely is an Amsterdam-based health IT company and one of the original co-developers of the HL7 FHIR (Fast Healthcare Interoperability Resources) specification. Co-founded by Ewout Kramer and Martijn Harthoorn (both long-time HL7 FHIR core team members), Firely builds the canonical FHIR toolchain used by payers, providers, health authorities, and digital health vendors worldwide. The Firely platform is anchored by Firely Server (formerly Vonk) — a certified production-grade FHIR server with native support for MongoDB and SQL Server, deployable on Windows, Linux, macOS, Docker, and Kubernetes across on-premise, Azure, AWS, and Google Cloud. Firely Server is G10, ONC, and ISiK certified and supports SMART on FHIR, Bulk Data, CDS Hooks, Subscriptions, Terminology Services, and FHIR Mapping. The product family also includes Simplifier.net (the global FHIR profile registry and package server hosting ~9,000 projects, 40,000+ profiles, and 1,600+ implementation guides), Forge (FHIR profile editor), Firely Terminal (command-line FHIR tool with FQL/FSH/FHIRPath support), the open-source Firely .NET SDK (the de-facto reference C# FHIR library), the firely-cql-sdk for Clinical Quality Language, the Firely Validator API, FHIR Facade, Firely Server Ingest, and Firely Auth. Customers include UCSF, Humana, Roche, NHS, Opala, and the World Health Organization. Firely does not operate a hosted multi-tenant FHIR-as-a-service offering with a public REST endpoint; customers run Firely Server in their own environments. The public developer surface is therefore the Firely software products (Firely Server, .NET SDK, Terminal), the Simplifier.net package and registry APIs, and the open HL7 FHIR REST API contract that every Firely Server instance implements.
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 Firely the way a machine reads it — 34 machine-readable artifacts across 1 API, 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 — Firely scores 27.1/100 (thin), with a separate agent-readiness read of 23/100 (agent aware). 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. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-08 · rubric v0.20.0
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title="Firely on API Evangelist — API profile and Kin Score">
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alt="Firely Kin Score — API readiness rating by API Evangelist" width="340" height="120" loading="lazy">
</a>More shapes, themes and sizes → · Score as JSON · How badges work
How we profile Firely
Each block below is one kind of artifact we hold for Firely. 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 3
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.
Firely Server FHIR REST API
Every Firely Server (formerly Vonk) instance exposes the standard HL7 FHIR REST API contract — type-level and instance-level CRUD, search, history, batch/transaction, capability...
Firely Catalog API
The Catalog API from Firely — 1 operation(s) for catalog.
Firely Simplifier.net FHIR Package API API
The Simplifier.net FHIR Package API API from Firely — 2 operation(s) for simplifier.net fhir package api.
Open Collections 4
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).
API Collection
OPEN COLLECTIONSimplifier.net FHIR Package Catalog API
OPEN COLLECTIONSimplifier.net FHIR Package API
OPEN COLLECTIONFeatures 25
The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.
Notable capabilities this provider offers.
Scroll within the panel for all 25 ·
Security Posture 1
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 Firely — 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.
Get Started 3
Portal, sign-up, and the first successful call
Documentation 6
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Build 22
SDKs, sample code, and the tooling you integrate with
Scroll within the panel for all 22 ·
Access & Security 1
Authentication, authorization, and security posture
Learn 2
Tutorials, courses, talks, and written guidance
Operate 1
Status, limits, changes, and where to get help
Commercial 1
Pricing, plans, and the legal terms of use
Company 4
The organization behind the API
Other 14
Properties that don't map to a standard resource type
Scroll within the panel for all 14 ·
← All providers · Data indexed from github.com/api-evangelist/firely-server · machine-readable index on apis.io
This is an independent, third-party profile of Firely, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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