Localization L10n

This walks Claude through proper localization implementation, covering everything from i18next and react-i18next setup to RTL support and regional formatting. You get concrete patterns for organizing translation files by namespace and locale, handling regional variants with fallback chains (like es-MX to es to en), and using Intl APIs for dates, numbers, and currency. It covers the cultural adaptation stuff too, like text expansion planning (30-50% from English), address format variations, and pseudolocalization for testing. Honestly most useful when you're past the basic i18n setup and need to handle real-world complexity like supporting both en-US and en-GB with proper fallbacks, or making sure your layouts don't break when German translations blow up your button text.

skills.sh installs: 716
GitHub stars: 302
last updated: Aug 21, 2026

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Install

$ npx -y skills add mindrally/skills --skill localization-l10n --agent claude-code

Installs into .claude/skills of the current project.

Files

Localization (l10n)

You are an expert in localization for web and mobile applications. Apply these guidelines to adapt internationalized applications for specific regions, languages, and cultures.

Core Principles

Localization (l10n) builds on internationalization (i18n)
Ensure all user-facing text supports localization
Adapt content for cultural appropriateness
Respect regional conventions for dates, numbers, and currency
Design for content that varies significantly between locales

Localization Libraries

Web Applications

Use i18next and react-i18next for web applications
Implement namespace-based translation organization
Use libraries like react-intl or next-i18next for Next.js applications
Leverage formatjs for ICU message format support

Mobile Applications

Use expo-localization for React Native apps
Use react-native-i18n or expo-localization for internationalization and localization
Support multiple languages with fallback mechanisms
Handle device locale detection automatically