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l20n v3.5.1

A localization library for Firefox OS

L20n: Localization 2.0 Build Status

L20n reinvents software localization. Users should be able to benefit from the entire expressive power of a natural language. L20n keeps simple things simple, and at the same time makes complex things possible.

L20n.js is a localization framework for websites which want to offer a best-in-class translation experience for their users. L20n takes advantage of modern web technologies to offer a fast and lean localization of HTML and JavaScript.

How to use L20n

Include the following code in the <head> section of your HTML:

<meta name="defaultLanguage" content="en-US">
<meta name="availableLanguages" content="de, en-US, fr, pl">
<link rel="localization" href="locales/myApp.{locale}.l20n">
<script defer src="dist/compat/web/l20n.js"></script>

L20n.js supports three kinds of translation resources:

  • L20n syntax, as documented at,
  • properties syntax: (deprecated),
  • JSON files parsed by tools/parse.js -o entries.

What L20n's syntax looks like

A straight-forward example in English:

<brandName "Firefox">
<about "About {{ brandName }}">
<preferences "{{ brandName }} Preferences">

And the same thing in Polish:

<brandName {
  nominative: "Firefox",
  genitive: "Firefoksa",
  dative: "Firefoksowi",
  accusative: "Firefoksa",
  instrumental: "Firefoksem",
  locative: "Firefoksie"
<about "O {{ brandName.locative }}">
<preferences "Preferencje {{ brandName.genitive }}">

Visit L20n by Example to learn more about L20n's syntax.

Localizing Web content with HTML Bindings

You can take advantage of HTML bindings to localize your HTML documents with L20n. See docs/html for documentation and examples.

The JavaScript API and documentation

It is also possible to use L20n programmatically, for instance in order to localize dynamic content. Refer to docs/node and docs/view for more details.


We'd love to hear your thoughts on L20n! Whether you're a localizer looking for a better way to express yourself in your language, or a developer trying to make your app localizable and multilingual, or a hacker looking for a project to contribute to, please do get in touch on the mailing list and the IRC channel.

Get Involved

L20n is open-source, licensed under the Apache License, Version 2.0. We encourage everyone to take a look at our code and we'll listen to your feedback.

We use Bugzilla to track our work. Visit our Tracking page for a collection of useful links and information about our release planning. You can also go straight to the Dashboard or file a new bug.

We <3 GitHub, but we prefer text/plain patches over pull requests. Refer to the Contributor's documentation for more information.


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