clerk-performance-tuning

name	clerk-performance-tuning
description	Optimize Clerk authentication performance. Use when improving auth response times, reducing latency, or optimizing Clerk SDK usage. Trigger with phrases like "clerk performance", "clerk optimization", "clerk slow", "clerk latency", "optimize clerk".
allowed-tools	Read, Write, Edit, Grep
version	1.14.0
license	MIT
author	Jeremy Longshore <[e-mail]>
tags	["saas","clerk","performance","authentication"]
compatibility	Designed for Claude Code, also compatible with Codex and OpenClaw

Clerk Performance Tuning

Overview

Optimize Clerk authentication for best performance. Covers middleware optimization, user data caching, token handling, lazy loading, and edge runtime configuration.

Prerequisites

• Clerk integration working
• Performance monitoring in place (Lighthouse, Web Vitals)
• Understanding of Next.js rendering strategies

Instructions

Step 1: Optimize Middleware (Skip Static Assets)

// middleware.ts — avoid running auth on static files
import { clerkMiddleware, createRouteMatcher } from '@clerk/nextjs/server'

const isPublicRoute = createRouteMatcher(['/', '/sign-in(.*)', '/sign-up(.*)', '/api/webhooks(.*)'])

export default clerkMiddleware(async (auth, req) => {
  if (!isPublicRoute(req)) {
    await auth.protect()
  }
})

// Restrict matcher to avoid processing static assets
export const config = {
  matcher: [
    // Skip _next, static files, and images
    '/((?!_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp|ico)).*)',
    '/(api|trpc)(.*)',
  ],
}

Step 2: Cache User Data

// lib/cached-user.ts
import { auth, currentUser } from '@clerk/nextjs/server'
import { cache } from 'react'

// React cache: deduplicates within a single request
export  getAuthUser = ( () => {
   { userId } =  ()
   (!userId)  
   ()
})