github.com/unicode-org/icu4x ↗

About unicode-org/icu4x

ICU4X is a Rust-based internationalization library designed for client-side and resource-constrained environments. Built by the Unicode Consortium's ICU4X Technical Committee, it provides components for wide-ranging software internationalization needs while drawing on decades of experience from the original ICU4C and ICU4J projects, the ECMA-402 standard, and data from the CLDR project. The library is fully implemented in Rust and emphasizes four core design goals: small and modular code, pluggable locale data, multi-language availability, and expert-driven best practices.

The project is architected to support multiple programming languages including JavaScript, Objective-C, Java, Dart, and C++, with an ECMA-402-compatible API surface targeting platforms such as the web, iOS, Android, WearOS, WatchOS, Flutter, and Fuchsia. This broad platform and language support makes it accessible to developers across different ecosystems while maintaining consistent internationalization capabilities. The modular approach allows applications to include only the components and locale data they need, keeping bundle sizes minimal for resource-constrained environments.

ICU4X is developed by the Unicode Consortium under open governance with a Technical Committee providing strategic direction and a Working Group handling day-to-day development and technical recommendations. The project is released under the Unicode License, a MIT-like license that explicitly covers both code and data, and contributors must sign a Contributor License Agreement.