Next.js Internationalization (i18n): Complete Setup Guide

Adding internationalization (i18n) to a Next.js application requires careful planning around routing, content management, and performance. Next.js 14's App Router provides excellent foundations for multi-language applications, and the ecosystem offers mature libraries that handle the complexities of server-side rendered internationalization.

For Next.js 14+, next-intl provides the most complete and well-maintained solution. It supports the App Router with server components, dynamic route segments for locale prefixes (domain.com/en/about, domain.com/fr/about), locale detection from browser settings, and TypeScript with full type safety. Alternative approaches include next-i18next (mature but primarily for Pages Router) and custom implementations using Next.js's built-in middleware for locale negotiation combined with a translation library of your choice.

Key implementation steps: install next-intl, configure locales in next.config.mjs, create JSON message files for each locale, implement locale detection middleware, wrap your app with the NextIntlClientProvider, and use the t() function in your components. For SEO, implement proper hreflang tags (next-intl handles this automatically), use canonical URLs with locale prefixes, and ensure all localized pages are accessible to search engines. Static site generation works with next-intl through generateStaticParams to pre-render all locale variants at build time.