Skip to content

i18next-fs-backend is a backend layer for i18next using in Node.js and for Deno to load translations from the filesystem.


Notifications You must be signed in to change notification settings


Repository files navigation


Actions Actions deno npm version

This is an i18next backend to be used in Node.js and Deno. It will load resources from the file system.

It's based on the deprecated i18next-node-fs-backend and can mostly be used as a drop-in replacement.

It will load resources from filesystem. Right now it supports following filetypes:

  • .json
  • .json5
  • .yml/.yaml
  • .js (very limited, checks for exports or export default)

Getting started

# npm package
$ npm install i18next-fs-backend

Wiring up:

import i18next from 'i18next';
import Backend from 'i18next-fs-backend';


for Deno:

import i18next from ''
import Backend from ''

  • As with all modules you can either pass the constructor function (class) to the i18next.use or a concrete instance.

Backend Options

  // path where resources get loaded from, or a function
  // returning a path:
  // function(lngs, namespaces) { return customPath; }
  // the returned path will interpolate lng, ns if provided like giving a static path
  loadPath: '/locales/{{lng}}/{{ns}}.json',

  // path to post missing resources
  addPath: '/locales/{{lng}}/{{ns}}.missing.json',

  // if you use i18next-fs-backend as caching layer in combination with i18next-chained-backend, you can optionally set an expiration time
  // an example on how to use it as cache layer can be found here:
  // expirationTime: 60 * 60 * 1000

Options can be passed in:

preferred - by setting options.backend in i18next.init:

import i18next from 'i18next';
import Backend from 'i18next-fs-backend';

  backend: options,

on construction:

import Backend from 'i18next-fs-backend';
const Backend = new Backend(null, options);

via calling init:

import Backend from 'i18next-fs-backend';
const Backend = new Backend();
Backend.init(null, options);


To properly type the backend options, you can import the FsBackendOptions interface and use it as a generic type parameter to the i18next's init method, e.g.:

import i18n from 'i18next'
import FsBackend, { FsBackendOptions } from 'i18next-fs-backend'

    backend: {
      // fs backend options

    // other i18next options

If set i18next initImmediate option to false it will load the files synchronously

// i18n.js
const { join } = require('path')
const { readdirSync, lstatSync } = require('fs')
const i18next = require('i18next')
const Backend = require('i18next-fs-backend')
    // debug: true,
    initImmediate: false,
    fallbackLng: 'en',
    lng: 'en',
    preload: readdirSync(join(__dirname, '../locales')).filter((fileName) => {
      const joinedPath = join(join(__dirname, '../locales'), fileName)
      const isDirectory = lstatSync(joinedPath).isDirectory()
      return isDirectory
    ns: 'backend-app',
    defaultNS: 'backend-app',
    backend: {
      loadPath: join(__dirname, '../locales/{{lng}}/{{ns}}.json')

Gold Sponsors