Clerk

Clerk is a comprehensive user management and authentication service built specifically for the modern web (React, Next.js, Remix). It focuses on providing "Drop-in" UI components (<SignIn />, <UserProfile />) rather than just APIs.

When to Use

• Next.js / React Apps: Best-in-class integration with App Router and Server Components.
• SaaS B2B/B2C: Built-in Organization (Multi-tenancy) management.
• Speed: You want the User Profile, Avatar upload, and Email management UI done for you.

Quick Start (Next.js App Router)

// middleware.ts
import { authMiddleware } from "@clerk/nextjs";
export default authMiddleware({});