Building a 9-Language Fan Site with Next.js 15 and next-intl (No Middleware)

I recently built a multilingual fan site for The Duskbloods , an upcoming FromSoftware game. The challenge: 9 languages (English, Japanese, Korean, Chinese, Spanish, French, German, Italian, Portuguese), static generation , and no middleware — all deployed on Cloudflare Workers. Here's how I did it and what I learned. The Architecture The site uses Next.js 15 App Router with next-intl v4 for internationalization. The key constraint: I wanted to avoid middleware to keep Cloudflare Worker costs down. src/ ├── app/ │ ├── (root)/ # English at / │ │ ├── gameplay/ │ │ ├── characters/ │ │ └── ... │ └── [locale]/ # Other languages at /zh, /ja, /ko... │ ├── gameplay/ │ ├── characters/ │ └── ... ├── messages/ # Translation files │ ├── en.json │ ├── ja.json │ ├── zh.json │ └── ... └── components/ # Shared components └── views/ Route Groups for Language Separation Instead of using middleware to detect locale, I use route groups : (root) — English content at the root path / [locale] — Other languages at /zh , /ja , /ko , etc. This means English gets clean URLs ( /gameplay ) while other languages get prefixed URLs ( /zh/gameplay ). Good for SEO — English is the default, and other languages have clear URL signals. Why No Middleware? Cloudflare Workers charge per request. Middleware runs on every request. For a static site with 9 languages, that's 9x the middleware invocations for every page load. By handling locale in the route, I skip middleware entirely. // src/app/[locale]/layout.tsx export async function generateStaticParams () { return [ ' ja ' , ' zh ' , ' ko ' , ' es ' , ' fr ' , ' de ' , ' it ' , ' pt ' ]. map ( locale => ({ locale })); } This pre-generates all locale variants at build time. Zero runtime locale detection. The Translation System Message Files Each locale has a JSON message file: // src/messages/zh.json { "gameplay" : { "intro" : { "eyebrow" : "玩法介绍" , "title" : "游戏机制" , "lead" : "深入了黄昏征讨的核心机制。" }, "virtue" : { "title" : "美德" , "types" : [ { "title" : "讨伐之美德