Clerk Has a Free API — Drop-In Authentication for React and Next.js

Clerk provides complete user management — sign-up, sign-in, user profiles, organizations, and MFA — with pre-built UI components that look great out of the box. Why Clerk? Pre-built components — <SignIn /> , <UserButton /> — production-ready UI Next.js middleware — protect routes with one line Organizations — multi-tenant auth built-in Free tier — 10,000 monthly active users Quick Start (Next.js) npm install @clerk/nextjs // middleware.ts import { clerkMiddleware } from ' @clerk/nextjs/server ' ; export default clerkMiddleware (); export const config = { matcher : [ ' /((?!.* \\ ..*|_next).*) ' , ' / ' , ' /(api|trpc)(.*) ' ] }; // app/layout.tsx import { ClerkProvider , SignedIn , SignedOut , SignInButton , UserButton } from ' @clerk/nextjs ' ; export default function RootLayout ({ children }) { return ( < ClerkProvider > < html > < body > < header > < SignedOut > < SignInButton /> </ SignedOut > < SignedIn > < UserButton /> </ SignedIn > </ header > { children } </ body > </ html > <