Clerk Cost Tuning

// Strategy 1: Defer authentication — don't force sign-in until necessary
// middleware.ts
import { clerkMiddleware, createRouteMatcher } from '@clerk/nextjs/server'

const requiresAuth = createRouteMatcher([
  '/dashboard(.*)',
  '/settings(.*)',
  '/api/protected(.*)',
])

export default clerkMiddleware(async (auth, req) => {
  // Only require auth for specific routes (not entire site)
  if (requiresAuth(req)) {
    await auth.protect()
  }
})

// Strategy 2: Use anonymous access for read-only features
// app/blog/[slug]/page.tsx
import { auth } from '@clerk/nextjs/server'

export default async function BlogPost({ params }: { params: { slug: string } }) {
  const { userId } = await auth() // Check but don't require
  const post = await db.post.findUnique({ where: { slug: params.slug } })

  return (
    <article>
      <h1>{post?.title}</h1>
      <div>{post?.content}</div>
      {userId ? <CommentForm /> : <p>Sign in to comment</p>}
    </article>
  )
}

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

// Deduplicate within single request (free)
export const getUser = cache(async () => {
  return currentUser()
})

// Cross-request caching reduces Backend API calls
import { unstable_cache } from 'next/cache'
import { clerkClient } from '@clerk/nextjs/server'

export const getUserMetadata = unstable_cache(
  async (userId: string) => {
    const client = await clerkClient()
    const user = await client.users.getUser(userId)
    return user.publicMetadata
  },
  ['user-metadata'],
  { revalidate: 600 } // 10-minute cache
)

// app/api/admin/clerk-usage/route.ts
import { auth, clerkClient } from '@clerk/nextjs/server'

export async function GET() {
  const { has } = await auth()
  if (!has({ role: 'org:admin' })) {
    return Response.json({ error: 'Admin only' }, { status: 403 })
  }

  const client = await clerkClient()
  const users = await client.users.getUserList({ limit: 1 })

  return Response.json({
    totalUsers: users.totalCount,
    // Estimate MRU based on recent sign-ins
    estimatedMRU: 'Check Clerk Dashboard > Billing for actual MRU',
    dashboardUrl: 'last-active?after=30d',
  })
}

// scripts/cleanup-inactive-users.ts
import { createClerkClient } from '@clerk/backend'

const clerk = createClerkClient({ secretKey: process.env.CLERK_SECRET_KEY! })

async function findInactiveUsers(daysInactive = 90) {
  const cutoff = Date.now() - daysInactive * 24 * 60 * 60 * 1000
  const allUsers = await clerk.users.getUserList({ limit: 500 })

  const inactive = allUsers.data.filter(
    (user) => (user.lastSignInAt || 0) < cutoff
  )

  console.log(`Found ${inactive.length} users inactive for ${daysInactive}+ days`)
  console.log('Consider: notification campaign, data export, or account cleanup')

  return inactive
}

findInactiveUsers()

function estimateMonthlyCost(mru: number): string {
  if (mru <= 50_000) return 'Free tier ($0/mo)'
  const overage = mru - 50_000
  const cost = 25 + overage * 0.02
  return `Pro tier: $${cost.toFixed(2)}/mo (${overage.toLocaleString()} extra MRU at $0.02 each)`
}

console.log(estimateMonthlyCost(15_000))  // "Free tier ($0/mo)"
console.log(estimateMonthlyCost(60_000))  // "Pro tier: $225.00/mo (10,000 extra MRU at $0.02 each)"