Cloudflare Next.js Deployment Skill

Deploy Next.js applications to Cloudflare Workers using the OpenNext Cloudflare adapter for production-ready serverless Next.js hosting.

When to Load References

Load additional reference files based on your specific task:

• references/error-catalog-extended.md - Load when encountering ANY error during setup, build, or deployment. Contains complete catalog of 11+ documented issues with root causes, solutions, and official sources.

• references/service-integration-patterns.md - Load when integrating Cloudflare services (D1, R2, KV, Workers AI) with Next.js. Contains complete patterns for database queries, file uploads, caching, and AI inference.

• references/troubleshooting.md - Load for general troubleshooting and debugging guidance beyond the error catalog.

• references/feature-support.md - Load when checking if a specific Next.js feature is supported on Cloudflare Workers (e.g., "Can I use Server Actions?", "Does ISR work?").

• references/database-client-example.ts - Load when integrating external database clients (Drizzle, Prisma, PostgreSQL, MySQL) with proper request-scoping patterns required by Workers.

• references/open-next.config.ts - Load when configuring caching behavior, image optimization, or custom OpenNext settings.

• references/package.json - Load when setting up a new project or migrating an existing Next.js application to Cloudflare Workers.

• references/wrangler.jsonc - Load when configuring Worker settings, compatibility flags, environment bindings (D1, R2, KV, AI), or deployment options.

Use This Skill When

• Deploying Next.js applications (App Router or Pages Router) to Cloudflare Workers
• Need server-side rendering (SSR), static site generation (SSG), or incremental static regeneration (ISR) on Cloudflare
• Migrating existing Next.js apps from Vercel, AWS, or other platforms to Cloudflare
• Building full-stack Next.js applications with Cloudflare services (D1, R2, KV, Workers AI)
• Need React Server Components, Server Actions, or Next.js middleware on Workers
• Want global edge deployment with Cloudflare's network

Key Differences from Standard Next.js

OpenNext Adapter transforms Next.js builds for Workers. Critical requirements:

• Node.js runtime (NOT Edge) via nodejs_compat flag
• Request-scoped database clients (global clients fail)
• Worker size limits: 3 MiB (free) / 10 MiB (paid)
• Dual testing: next dev for speed, preview for production-like validation

Setup Patterns

New Project Setup

Use Cloudflare's create-cloudflare (C3) CLI to scaffold a new Next.js project pre-configured for Workers:

npm create cloudflare@latest -- my-next-app --framework=next

What this does:

1. Runs Next.js official setup tool (create-next-app)
2. Installs @opennextjs/cloudflare adapter
3. Creates wrangler.jsonc with correct configuration
4. Creates open-next.config.ts for caching configuration
5. Adds deployment scripts to package.json
6. Optionally deploys immediately to Cloudflare

Development workflow:

npm run dev      # Next.js dev server (fast reloads)
npm run preview  # Test in workerd runtime (production-like)
npm run deploy   # Build and deploy to Cloudflare

Existing Project Migration

To add the OpenNext adapter to an existing Next.js application:

1. Install the adapter

bun add -d @opennextjs/cloudflare

Secure Installation

Adapter packages handle production traffic — pin exact versions and audit before upgrading. Follow supply chain security best practices:

• Block post-install scripts — npm config set ignore-scripts true (or Bun: disabled by default)
• Cooldown period — Wait 7 days for new package versions to be vetted by the community
• Audit before installing — Run socket package score npm <pkg> or use socket npm install <pkg> to check packages

Load the dependency-upgrade skill for full security configuration including Socket CLI integration, cooldown setup, lockfile validation, and CI enforcement.

2. Create wrangler.jsonc

{
  "name": "my-next-app",
  "compatibility_date": "2025-05-05",
  "compatibility_flags": ["nodejs_compat"]
}

Critical configuration:

• compatibility_date: Minimum 2025-05-05 (for FinalizationRegistry support)
• compatibility_flags: Must include nodejs_compat (for Node.js runtime)

3. Create open-next.config.ts

import { defineCloudflareConfig } from "@opennextjs/cloudflare";

export default defineCloudflareConfig({
  // Caching configuration (optional)
  // See: https://opennext.js.org/cloudflare/caching
});

4. Update package.json scripts

{
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "preview": "opennextjs-cloudflare build && opennextjs-cloudflare preview",
    "deploy": "opennextjs-cloudflare build && opennextjs-cloudflare deploy",
    "cf-typegen": "wrangler types --env-interface CloudflareEnv cloudflare-env.d.ts"
  }
}

Script purposes:

• dev: Next.js development server (fast iteration)
• preview: Build + run in workerd runtime (test before deploy)
• deploy: Build + deploy to Cloudflare
• cf-typegen: Generate TypeScript types for Cloudflare bindings

5. Ensure Node.js runtime (not Edge)

Remove Edge runtime exports from your app:

// ❌ REMOVE THIS (Edge runtime not supported)
export const runtime = "edge";

// ✅ Use Node.js runtime (default)
// No export needed - Node.js is default

Development Workflow

Dual Testing Required:

• npm run dev - Fast iteration (Next.js dev server)
• npm run preview - Production-like testing (workerd runtime, REQUIRED before deploy)
• npm run deploy - Build and deploy

Critical: Always test preview before deploying to catch Workers-specific runtime issues

Critical Configuration

wrangler.jsonc minimum requirements:

{
  "compatibility_date": "2025-05-05",  // Minimum for FinalizationRegistry
  "compatibility_flags": ["nodejs_compat"]  // Required for Node.js runtime
}

Cloudflare Bindings: Add D1, R2, KV, or AI bindings in wrangler.jsonc, access via process.env (see "Cloudflare Services Integration" section for complete patterns)

Package Exports (if needed): Create .env with WRANGLER_BUILD_PLATFORM="node" to prioritize Node.js exports

Top 5 Critical Errors

These are the most common deployment-blocking errors. For the complete catalog of 11+ errors, load references/error-catalog-extended.md.

1. Worker Size Limit Exceeded

Error: "Your Worker exceeded the size limit of 3 MiB" (Free) or "10 MiB" (Paid)

Quick Fix: Upgrade plan, analyze bundle with bunx opennextjs-cloudflare build → check .open-next/server-functions/default/handler.mjs.meta.json, remove unused dependencies, or use dynamic imports.

Source: https://opennext.js.org/cloudflare/troubleshooting#worker-size-limits

2. Cannot Perform I/O on Behalf of Different Request

Error: "Cannot perform I/O on behalf of a different request"

Cause: Global database client reused across requests (Workers limitation)

Quick Fix: Create database clients INSIDE request handlers, never globally. Or use Cloudflare D1 which is designed for Workers.

// ❌ WRONG: Global client
const pool = new Pool({ connectionString: process.env.DATABASE_URL });

// ✅ CORRECT: Request-scoped
export async function GET() {
  const pool = new Pool({ connectionString: process.env.DATABASE_URL });
  // ... use pool
  await pool.end();
}

Source: https://opennext.js.org/cloudflare/troubleshooting#cannot-perform-io-on-behalf-of-a-different-request

3. NPM Package Import Failures

Error: "Could not resolve '<package>'"

Quick Fix: Enable nodejs_compat flag in wrangler.jsonc, and/or create .env with WRANGLER_BUILD_PLATFORM="node".

**Source