Localize will officially launch next Monday. I’ve got a full week of launch activity planned. And a shiny new blog at elixir-localize.com where I’m committed to spending more time writing about they why and how localisation matters and how localize can make it almost trivial to write localised Elixir applications.

Each day next week there is something launching:

• Monday is the core localize library. It compiles faster than ex_cldr, runs faster, uses less memory, has simpler packaging (nearly everything in one package).

• Tuesday is localize_web that includes accept-header parsing and locale setting, localised routes and some HTML helpers.

• Wednesday is the launch of localize_person_names for formatting names in a localised manner; in formal, informal and other ways. And the launch of Calendrical which is a consolidated set of calendars now including Gregorian, Julian, Islamic (four variants), Hebrew, Persian, Indian, Buddhist, Composite and user definable. And a few more I probably missed.

• Thursday its time for some new fun things. localize_phonenumber that wraps libphonenumber for parsing and formatting phone numbers and localize_address for parsing free-form address data and then formatting its using the OpenCageData templates.

• Friday is the “one more thing” release. It’s called Intl and its an API wrapper for Localize that maps very closely to the Javascript Intl API. This should make it easier for developers who are more front-end savvy to adopt localisation in Elixir more easily.

I’ll be posting more long form content at elixir-localize.com as the week progresses.

Eight years into developing ex_cldr and friends I think I can say confidently that localize is better in every way. I hope you’ll try it out, give feedback, open issues and help me make that claim a reality.

Day #1 of Localize launch week and Localize version 0.1.0 is now live on hex. It brings 8 years of experience of building ex_cldr together with a revised and simplified architecture, more capabilities, greater CLDR conformance, faster performance and better developer experience.

My hope is that localize will encourage more developers to build localisation into their apps from the beginning. Whether you plan to deliver an app in a single locale or many, localize just makes it easier. In a single library you get just about everything CLDR can deliver to make localisation and personalisation a pleasurable experience.

It’s a 0.1.0 release but its build on years of experience from ex_cldr. It will look very similar to developers who have used ex_cldr, but there are tons of changes and additions too. So I expect a few rough edges and I would really encourage anyone jumping on board to open issues or start a discussion. I think it won’t take too long to get to a 1.0 release.

I’ll also be blogging about the changes in localize, about localisation in general and about tips and trick on the Elixir Localize blog. There’s an RSS feed too. The blog is built using static_blog that I build for the site - but you might find it useful too.

Design goals met

• No backend architecture, runtime everything.
• Compiles and runs faster than ex_cldr. A performance report details the performance improvements.
• Consistent error returns - always {:error, exception} with exception messages that can be translated through gettext
• An opt-in NIF for several of the formatters - hint, the NIF is not always faster!
• Improved documentation and a series of guides: Number formatting, Date and Time formatting, Units of Measure formatting, Message Formatting and Collation
• Pluggable behaviour for locale loading, storing and accessing with a default that stores data in :persistent_term
• Locales are hosted on Cloudflare R2 and downloaded with mix localize.download_locales or can be configured to be downloaded dynamically at runtime from https://elixir-localize/locales. This is more reliable that using Github as a CDN and faster for many people.

Migrating from ex_cldr

If you’re migrating from ex_cldr, the migration guide will help. The overall API will look very familiar, with the most obvious change being that there is never a backend function argument or option.

And of course you don’t need to juggle multiple libraries, deal with compile-time configuration or generate backend modules.

Functional Highlights

• Current CLDR v48.2 locale data with lazy runtime loading from ETF files cached in :persistent_term. No compile-time backend configuration required.

• Number formatting — integers, decimals, percentages, currencies, ranges, and rule-based number formats (RBNF) including Roman numerals and CJK ideographs.

• Date, time, and datetime formatting using CLDR calendar patterns with :short, :medium, :long, and :full styles, custom skeleton patterns, and interval formatting.

• Unit formatting with plural-aware patterns, SI/binary prefixes, compound units, measurement system conversion, custom unit registration, and Localize.Unit.Operators for natural arithmetic (km + m).

• List formatting with locale-appropriate conjunctions, disjunctions, and unit list styles. Per-element formatting via Localize.Chars.

• ICU MessageFormat 2 (MF2) parser and interpreter with custom function registry, offset selection, JSON interchange, and bidirectional text support.

• Gettext integration — Localize.Gettext.Interpolation provides MF2-based interpolation for Gettext backends.

• Localize.Chars protocol — polymorphic locale-aware formatting with built-in implementations for 14 types and Any fallback to Kernel.to_string/1.

• Currency metadata, ISO 4217 validation, and territory-to-currency mapping.

• Display names for territories, languages, scripts, calendars, and full locale display names per the CLDR algorithm.

• Unicode Collation Algorithm (UCA) with CLDR locale-specific tailoring for 97 languages, including digraph expansion and script reordering.

You absolute legend.