Clerk
Clerk is a drop-in authentication and user management platform for web and mobile applications. The product spans sign-up / sign-in flows, user profiles, multi-factor authentication, passkeys, social sign-on, magic links, bot and fraud detection, organizations (B2B / multi-tenant) with custom roles and invitations, and a Billing product for subscriptions. The Backend API at api.clerk.com is authenticated with a Bearer secret key and has an OpenAPI specification. Frontend SDKs cover Next.js, React, React Router, Expo, Astro, TanStack React Start, Chrome Extension, and vanilla JavaScript. Backend SDKs cover Node, Go, Python, Ruby, Java, PHP, and C#. Webhooks are delivered via Svix.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles Clerk the way a machine reads it — 35 machine-readable artifacts across 24 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 — Clerk scores 49.5/100 (developing), 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 Clerk
Each block below is one kind of artifact we hold for Clerk. 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 24
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.
Clerk Frontend API
Browser-facing API consumed by Clerk's frontend SDKs and ClerkJS for sign-up, sign-in, session refresh, and user profile mutations. Endpoint is instance-specific (subdomain on c...
Clerk Webhooks (Svix)
Webhook events delivered via Svix for user, session, organization, email, SMS, and role lifecycle changes. Customers configure endpoints in the dashboard and verify signatures w...
Clerk JavaScript SDK
Official ClerkJS browser library and monorepo of framework adapters (Next.js, React, Expo, React Router, Astro, Chrome Extension, TanStack). Powers Clerk's prebuilt UI component...
Clerk Next.js SDK
Next.js integration covering App Router and Pages Router, middleware, route handlers, server components, and server actions. Distributed from the @clerk/nextjs package inside th...
Clerk React SDK
React components, hooks, and providers from the @clerk/clerk-react package for plain React SPAs.
Clerk Expo SDK
Expo / React Native bindings for Clerk supporting OAuth via deep links, secure session storage, and biometrics.
Clerk React Router SDK
Adapter for React Router v7 (Remix successor) covering loaders, actions, and server-rendered authentication.
Clerk Astro SDK
Adapter for the Astro framework with components and middleware.
Clerk TanStack Start SDK
Adapter for TanStack Start (React full-stack framework) with route-level authentication helpers.
Clerk Node.js SDK
Backend SDK for Node.js (@clerk/backend / @clerk/express / @clerk/fastify) that wraps the Backend API and verifies session JWTs.
Clerk Go SDK
Official Go SDK for the Clerk Backend API.
Clerk Python SDK
Official Python SDK for the Clerk Backend API.
Clerk Ruby SDK
Official Ruby SDK for the Clerk Backend API, with a Rails integration.
Clerk Java SDK
Official Java SDK for the Clerk Backend API.
Clerk PHP SDK
Official PHP SDK for the Clerk Backend API.
Clerk C# / .NET SDK
Official C# / .NET SDK for the Clerk Backend API.
Clerk OpenAPI Specifications
Public repository of OpenAPI specifications for Clerk's APIs, used as the source for generated SDKs and documentation.
Clerk Invitations API
The Invitations API from Clerk — 2 operation(s) for invitations.
Clerk JwtTemplates API
The JwtTemplates API from Clerk — 1 operation(s) for jwttemplates.
Clerk Organizations API
The Organizations API from Clerk — 4 operation(s) for organizations.
Clerk Sessions API
The Sessions API from Clerk — 4 operation(s) for sessions.
Clerk SignInTokens API
The SignInTokens API from Clerk — 2 operation(s) for signintokens.
Clerk Users API
The Users API from Clerk — 4 operation(s) for users.
Clerk Webhooks API
The Webhooks API from Clerk — 1 operation(s) for webhooks.
Scroll within the panel for all 24 ·
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).
Clerk Backend API
OPEN COLLECTIONGraphQL 1
Where a provider ships GraphQL, the schema is the contract. We profile it alongside the REST surface so the whole interface is legible in one place.
GraphQL schemas published by this provider.
Clerk GraphQL
Clerk's public API surface is REST-based. The Backend API lives at `https://api.clerk.com/v1` and is documented at [https://clerk.com/docs/reference/backend-api](https://clerk.c...
GRAPHQLPricing 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.
Clerk Plans Pricing
PLANSRate 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.
Clerk 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.
Clerk 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.
Clerk Webhooks
AsyncAPI 2.6 specification for Clerk's webhook surface. Clerk delivers webhook events via Svix to customer-configured endpoints. Each delivery is an HTTP POST of a JSON envelope...
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.
Clerk API Rules
SPECTRALSecurity Posture 3
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 Clerk — 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 2
MCP servers, agent skills, and machine-readable catalogs
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 3
Authentication, authorization, and security posture
Operate 2
Status, limits, changes, and where to get help
Commercial 1
Pricing, plans, and the legal terms of use
Company 3
The organization behind the API
← All providers · Data indexed from github.com/api-evangelist/clerk · machine-readable index on apis.io