Getting Started

There are two configuration files that are necessary for ni18n to work as expected in most cases. The nextjs.config.js and a file to hold ni18n's own configuration. Then you will need the translations files for your application and to setup your pages/_app file accordingly in order to be able to use the translations in your application.

1. Next.js config

Setup the next config file according to your needs by following the documentation on next.js i18n-routing

// next.config.js
module.exports = {
  i18n: {
    defaultLocale: 'en',
    locales: ['en', 'es'],
  },
}

2. Ni18n config

The ni18n config works pretty much as an i18next config does. With a few minor differences listed in the F.A.Q..

But the basic setup is pretty simple.

// ni18n.config.ts
import type { Ni18nOptions } from 'ni18n'

export const ni18nConfig: Ni18nOptions = {
  supportedLngs: ['en', 'es'],
  ns: ['your-default-namespace', 'your-other-namespaces...'],
}

i18next >= 21 The first item in the ns array will be set as your default and allow you to call useTranslation() without any parameters to use it. If you want to manually select the default, then you can set the defaultNS property.

Note: The name and location of the file don't really matter, you can call it anything and put it anywhere you want.

3. Translation Files

You will also need to provide the translation files for your application. They are expected to be on the public folder. The default structure is /public/locales/{{lng}}/{{ns}}.json, but it can be changed following the instructions here

Example of how your folder structure should look like.

./public
└── locales
    ├── language1
    │   ├── namespace1.json
    │   └── namespace2.json
    └── language2
        ├── namespace1.json
        └── namespace2.json

4. Next.js App

Translations won't work without a I18nextProvider, so we need to set it up. It is required to wrap your App with the appWithI18Next function provided by ni18n. Which will initialize the i18next instance and provide it as a context for all the children. You can read more about Next.js Custom App in their documentation.

// pages/_app.tsx
import { appWithI18Next } from 'ni18n'
import { ni18nConfig } from '../ni18n.config'

const MyApp = ({ Component, pageProps }) => <Component {...pageProps} />

export default appWithI18Next(MyApp, ni18nConfig)

5. Using Translations

Finally, you can call useTranslation on your files, or any other react-i18next component you may need.

// my-component.tsx
import { useTranslation } from 'react-i18next'

export const MyComponent = () => {
  const { t } = useTranslation()
  return <>{t('myKey')}</>
}

Caveats

Client Side vs Server Side

At this point, all your translation files will be loaded on the client side, if you need them loaded on the server, read more on Server Side Loading

We also recommend to always use either loadTranslations or clientNamespaces or both in a page, else you will load all the namespaces on your application for every page.

Importing

ni18n only exports appWithI18Next, loadTranslations, clientNamespaces and useSyncLanguage. All other functions you need can be imported from react-i18next or i18next directly.