# Clerk

**Canonical:** https://apis.io/providers/clerk/  
**Website:** https://clerk.com/  
**APIs profiled:** 24

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.

## Kin Score — 45.4 / 100 (developing)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 45.4).

| Facet | Score |
|---|---|
| Discoverability | 81.5 |
| Contract Quality | 65.7 |
| Governance | 11.4 |
| Contract Governance | 11.4 |
| Operational Transparency | 52.6 |
| Developer Ergonomics | 23.8 |
| Commercial Clarity | 39.5 |
| Access Clarity | 39.5 |

## Agent readiness — 30.3 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | yes |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | documented |
| Event Surface Described | derived |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Free · Self-serve signup — onboarding: self-serve, pricing: free, trial: no (confidence: high).

## APIs (24)

- **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.

## Agentic access (1)

- **Clerk Agentic Access** — 29 operations · 19 acting · 3 human-in-the-loop

## Security (3)

- **Clerk Authentication** — http · 1 scheme
- **Clerk Domain Security** — TLSv1.3 · HSTS · DMARC
- **Clerk Vulnerability Disclosure** — security.txt · contact published

## Plans (1)

- **Clerk Plans Pricing**

## Tags

Authentication, User Management, Identity, Passkeys, MFA, B2B, Organization, Billing

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/clerk/). Scores are computed from the provider's own public artifacts under a published rubric.