next-intl

What is next-intl?

The next-intl package is designed to provide internationalization (i18n) support for Next.js applications. It allows developers to easily manage translations, handle locale routing, and format dates, numbers, and other content according to locale-specific rules.

What are next-intl's main functionalities?

Translation Management

This feature allows you to manage translations for different components. The `useTranslations` hook is used to fetch the translations for a specific namespace, and you can then use the translation keys to display localized text.

import { useTranslations } from 'next-intl';

export default function MyComponent() {
  const t = useTranslations('MyComponent');
  return <p>{t('hello')}</p>;
}

Locale Routing

This feature allows you to handle locale-specific routing in your Next.js application. By using the `useRouter` hook, you can programmatically change the locale and update the URL accordingly.

import { useRouter } from 'next/router';

export default function LocaleSwitcher() {
  const router = useRouter();
  const changeLocale = (locale) => {
    router.push(router.pathname, router.asPath, { locale });
  };
  return (
    <div>
      <button onClick={() => changeLocale('en')}>English</button>
      <button onClick={() => changeLocale('fr')}>French</button>
    </div>
  );
}

Date and Number Formatting

This feature allows you to format dates, numbers, and other content according to locale-specific rules. The `useIntl` hook provides methods like `formatDate` to format dates in a localized manner.

import { useIntl } from 'next-intl';

export default function DateFormatter() {
  const intl = useIntl();
  const formattedDate = intl.formatDate(new Date(), { year: 'numeric', month: 'long', day: 'numeric' });
  return <p>{formattedDate}</p>;
}

Other packages similar to next-intl

react-intl

react-intl is a popular library for internationalizing React applications. It provides similar functionalities to next-intl, such as translation management and date/number formatting. However, it does not offer built-in support for Next.js-specific features like locale routing.

i18next

i18next is a powerful internationalization framework that can be used with various JavaScript libraries, including React. It offers extensive features for managing translations, handling pluralization, and more. While it is more versatile, it requires additional setup to integrate with Next.js compared to next-intl.

next-translate

next-translate is another Next.js-specific internationalization library. It provides similar functionalities to next-intl, such as translation management and locale routing. However, next-translate uses a different approach for loading translations and may have different performance characteristics.

README

Internationalization (i18n) for Next.js

Features

Internationalization (i18n) is an essential part of the user experience, therefore next-intl gives you all the parts you need to get language nuances right.

• 🌟 ICU message syntax: Localize your messages with interpolation, cardinal & ordinal plurals, enum-based label selection and rich text.
• 📅 Dates, times & numbers: Apply appropriate formatting without worrying about server/client differences like time zones.
• ✅ Type-safe: Speed up development with autocompletion for message keys and catch typos early with compile-time checks.
• 💡 Hooks-based API: Learn a single API that can be used across your code base to turn translations into plain strings or rich text.
• 🚀 Next.js-native and performance-obsessed: App Router, Server Components, static rendering—pick the right tool for the right job, next-intl works everywhere.
• ⚔️ Internationalized routing: Provide unique pathnames per language and optionally localize pathnames for search engine optimization.

What does it look like?

// UserProfile.tsx
import {useTranslations} from 'next-intl';

export default function UserProfile({user}) {
  const t = useTranslations('UserProfile');

  return (
    <section>
      <h1>{t('title', {firstName: user.firstName})}</h1>
      <p>{t('membership', {memberSince: user.memberSince})}</p>
      <p>{t('followers', {count: user.numFollowers})}</p>
    </section>
  );
}

// en.json
{
  "UserProfile": {
    "title": "{firstName}'s profile",
    "membership": "Member since {memberSince, date, short}",
    "followers": "{count, plural, ↵
                    =0 {No followers yet} ↵
                    =1 {One follower} ↵
                    other {# followers} ↵
                  }"
  }
}

→ Read the docs

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