Last modified: April 04, 2022Author:Β Jakub PomykaΕ‚a

next-i18next and SimpleLocalize example

Documentation article has been written based on content of GitHub Repository.

Translations location

Put your translations in /public/locales/{lang}/{ns}.json

  • {ns} - namespace, allows you to split translation keys into multiple files
  • {lang} - language

In this example there are two namespaces: common and home and 4 locales: en, es, fr_FR, pl.

β”œβ”€β”€ en
β”‚   β”œβ”€β”€ common.json
β”‚   └── home.json
β”œβ”€β”€ es
β”‚   β”œβ”€β”€ common.json
β”‚   └── home.json
β”œβ”€β”€ pl
β”‚   β”œβ”€β”€ common.json
β”‚   └── home.json
└── fr_FR
    β”œβ”€β”€ common.json
    └── home.json

i18next configuration

Install i18next for NextJS

npm install --save next-i18next

Create a configuration file in project root.

// πŸ“¦ file: ./next-i18next.config.js
module.exports = {
  i18n: {
    defaultLocale: 'en',
    locales: ['en', 'es', 'pl', 'fr_FR'],

NextJS i18n configuration

Import i18next configuration file into next.config.js

// πŸ“¦ file: ./next.config.js
const {i18n} = require("./next-i18next.config");
const nextConfig = {
  reactStrictMode: true,

module.exports = nextConfig

SimpleLocalize configuration

πŸ’Ώ Install SimpleLocalize CLI

curl -s | bash

🧷 Create configuration file

# πŸ“¦ file: ./simplelocalize.yml
downloadFormat: single-language-json
downloadPath: ./public/locales/{lang}/{ns}.json

uploadFormat: single-language-json
uploadPath: ./public/locales/{lang}/{ns}.json

‡️ Download translations to ./public/locales directory

simplelocalize download

‴️ Upload translations from ./public/locales directory

simplelocalize upload

You can automate process of adding translation keys from project to SimpleLocalize.


Example usage can be found in pages/index.tsx.

//translations from common.json
const {t} = useTranslation('common');
console.log(t('LEARN_MORE')) // output: Learn more

//translations from home.json
const {t: homeT} = useTranslation('home');
console.log(homeT('HELLO_WORLD')) // output: Hello world

Try out this demo

First, download source code from GitHub:

and run the development server:

npm run dev

Open http://localhost:3000 with your browser to see the result.

You can start editing the page by modifying pages/index.tsx. The page auto-updates as you edit the file.