Clerk

Flutter

Google's UI toolkit for building natively compiled applications for mobile, web, and desktop from a single codebase.

Open Source

Frontend Frameworks

3/5

Clerk publishes an official clerk_flutter SDK (currently in beta) bringing Clerk authentication and user management to Flutter apps.

NestJS

Progressive Node.js framework for building efficient, scalable server-side applications with TypeScript and modular architecture.

Open Source

Backend Frameworks

4/5

Clerk integrates natively with NestJS via Passport strategy and JWT middleware — a common auth solution for Angular/NestJS full-stack apps.

Spring Boot

Spring Boot is an opinionated Java framework that simplifies the creation of production-ready Spring applications with minimal configuration and embedded servers.

Open Source

Backend Frameworks

4/5

Clerk integrates with Spring Boot via JWT token verification — used when Spring Boot serves as the backend API for a Next.js + Clerk frontend.

Express

Express is a minimal, unopinionated Node.js web framework that adds routing and middleware on top of Node's HTTP server. It is the most widely used Node.js backend framework and the base of higher-level frameworks like NestJS.

Open Source

Backend Frameworks

3/5

Clerk can protect Express APIs via JWT verification — used when an Express backend serves an authenticated React/Next.js frontend managed by Clerk.

Reflex

Full-stack Python web framework that compiles Python components into a React frontend and keeps app state in a Python backend, so web apps are built without JavaScript.

Freemium

Data Apps

3/5

Clerk integrates with Reflex through reflex-clerk-api, an actively maintained community custom-component package that wraps Clerk's hosted sign-in UI and verifies sessions from Reflex's Python backend.

Next.js

Next.js is a React meta-framework by Vercel for building full-stack web applications, offering the App Router with React Server Components, hybrid static/SSR rendering, API routes, server actions, and Turbopack-powered builds. It is the most widely adopted React framework for production applications.

Open Source

Frontend Frameworks

5/5

Official @clerk/nextjs SDK with App Router middleware, server-side session handling, and prebuilt components.

React

React is the most widely used JavaScript library for building user interfaces through reusable components. Created by Meta, it powers web and native apps at massive scale.

Open Source

Frontend Frameworks

4/5

Clerk has a first-class React SDK (@clerk/react) with pre-built sign-in/sign-up components and hooks — commonly paired with React in Next.js projects.

Convex

Modern application backend with database, backend functions, and real-time sync. Designed for frontend developers.

Freemium

Databases

4/5

Clerk publishes an official Convex integration (@clerk/clerk-react + Convex's own convex/react-clerk helpers) for wiring Clerk-issued JWTs into Convex's auth system.

Replit

Replit is a browser-based collaborative IDE and AI app builder whose Agent plans, writes, debugs, and deploys full applications from natural language, with built-in hosting, databases, and secrets management.

Freemium

AI Builders

3/5

Replit officially partners with Clerk ("Clerk for Platforms"): Replit provisions and configures a dedicated Clerk instance on the user's behalf, with a documented migration path from Replit Auth, and recommends Clerk for external-facing apps.

Auth0

Auth0 is Okta's enterprise identity platform, with hosted Universal Login, social and enterprise SSO, MFA, passwordless, and machine-to-machine authorization for web, mobile, and API apps.

Freemium

Authentication

5/5

Both hosted auth-as-a-service platforms; Clerk is newer with better developer UX and prebuilt UI components, Auth0 is enterprise-proven with broader compliance certifications.

Supabase Auth

Supabase Auth is the open-source authentication service built into Supabase, tied to PostgreSQL Row Level Security so the signed-in user's identity drives database access rules.

Freemium

Authentication

4/5

Supabase Auth is bundled with the Supabase platform; Clerk is a standalone auth service with richer prebuilt UI components and session management.

BetterAuth

Open-source TypeScript authentication framework that runs inside your app, covering email and password, social OAuth, passkeys, multi-tenancy, and SSO with no per-user pricing, plus an optional paid dashboard.

Freemium

Authentication

4/5

BetterAuth is the self-hosted open-source alternative to Clerk — same auth scope (email, OAuth, passkeys, organisations) but runs inside your app with no third-party data custody or per-MAU pricing.

Firebase Auth

Google's authentication service with deep integration across Firebase platform and extensive mobile SDK support.

Freemium

Authentication

4/5

Firebase Auth is tied to the Firebase ecosystem; Clerk is standalone with richer customizable prebuilt UI and organization management.

Keycloak

Open-source identity and access management platform with SSO, SAML 2.0, OIDC, and LDAP/AD federation — self-hosted, no per-user pricing.

Open Source

Authentication

3/5

Keycloak is an enterprise IAM alternative to Clerk — self-hosted, protocol-standards-based (OIDC/SAML), and suited to organisations that need LDAP/AD integration or SSO across many internal applications rather than a per-app auth service.