Clerk Authentication Patterns

Quick Guide: Clerk provides managed authentication with pre-built UI components, server-side helpers, and organization-based multi-tenancy. Use clerkMiddleware() for route protection, <Show> for conditional rendering, hooks for client state, and auth()/currentUser() for server-side auth. Clerk Core 3 (2026) replaces <SignedIn>/<SignedOut> with <Show>, renames the middleware file to proxy.ts (Next.js 16+), and consolidates packages.

<critical_requirements>

CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST use @clerk/nextjs/server for ALL server-side imports -- NEVER import server helpers from @clerk/nextjs)

(You MUST verify webhooks using Clerk's verifyWebhook helper -- NEVER trust unverified webhook payloads)

(You MUST use <Show> component instead of deprecated <SignedIn>/<SignedOut>/<Protect> -- these are removed in Core 3)

(You MUST NOT pass the full currentUser() object to the client -- it contains privateMetadata that must stay server-side)