Natural Cycles
Natural Cycles is a Swedish women's-health company behind the first birth-control application cleared by the US FDA (2018) and CE-marked in Europe as a Class IIb medical device. Its subscription app uses a proprietary temperature-based algorithm to identify fertile and non-fertile days from a user's daily basal body temperature, supporting both preventing and planning pregnancy as well as cycle, ovulation, and perimenopause tracking. Temperature is captured with a paired Bluetooth basal thermometer or through consumer wearables the app integrates with — Apple Watch, Oura Ring, and the NC B1 band. Natural Cycles publishes clinical research, an educational content library (CycleMatters), an e-commerce shop for thermometers and tests, and a public bug-bounty / responsible-disclosure program, but it does not expose a public developer API, developer portal, or OpenAPI. Backed by EQT Ventures.
Index entry only — little beyond a description and a link, and nothing machine-readable enough for an agent to act on without a human reading the site first.
API Evangelist profiles Natural Cycles the way a machine reads it — 2 machine-readable artifacts, 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 — Natural Cycles scores 13.6/100 (minimal), with a separate agent-readiness read of 7/100 (human only). 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 Natural Cycles
Each block below is one kind of artifact we hold for Natural Cycles. 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.
Security 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.
Resources
Every other property we hold for Natural Cycles — 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.
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Access & Security 4
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 2
The organization behind the API
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