MessageFormat 2

MessageFormat 2 (MF2) is an upcoming standard for software internationalization developed by the Unicode Consortium. Kanjou relies on MF2 to define and format all localized messages.

Why MF2 over ICU MessageFormat 1?

If you've used tools like react-intl, you're likely familiar with ICU MessageFormat 1. While MF1 has served the industry well, it has several limitations that MF2 aims to solve:

• Cleaner Syntax: MF2 introduces a much more readable, structured syntax, avoiding the deeply nested "curly brace hell" of MF1 plurals and selects.
• Modularity & Data Model: MF2 is designed with a formal data model, making it easier to parse, analyze, and build tooling around (which is how Kanjou provides strict type safety).
• First-Class Markup: MF2 natively supports markup tags, which is perfect for formatting rich text or embedding React components without breaking the flow of translations.