# localization-l10n

Guides AI coding assistants through localization best practices. It helps configure translation files, regional Intl formatting, and RTL layouts.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 689 installs · ★ 286
- Author: Mindrally
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/Mindrally/skills/tree/HEAD/localization-l10n/SKILL.md
- Updated: 2026-10-08
- HTML: https://affpapa.org/en/nevibecode/skills/localization-l10n

## What it does

The skill instructs coding models on configuring libraries like `i18next` or `expo-localization`. It establishes namespace structures for translation files. This keeps large dictionaries manageable. It also creates fallback chains for regional language variants and details compliance requirements for local regulations.

Fixed-width containers break interfaces during translation. German text expands by 30-50% compared to English. Because of this, the skill directs the model toward flexible layouts and CSS logical properties for right-to-left scripts. It also handles currency and date formatting with standard `Intl` APIs.

Quality assurance relies on pseudolocalization. It catches hardcoded strings before code reaches production. The guidance also details namespace lazy loading and automatic browser locale detection.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill localization-l10n -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/localization-l10n/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/localization-l10n/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill localization-l10n -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/localization-l10n/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill localization-l10n -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/localization-l10n/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install Mindrally/skills localization-l10n
```

2. **Manually: put the files in place**
- File: `.github/skills/localization-l10n/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill localization-l10n -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/Mindrally/skills --path localization-l10n
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/localization-l10n/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add Mindrally/skills --skill localization-l10n -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/Mindrally/skills/tree/HEAD/localization-l10n/SKILL.md

## When to use it
- organize translation files with regional fallback chains
- format dates, numbers, and currencies using the native `Intl` API
- adapt component styling to CSS logical properties for RTL
- catch hardcoded strings using pseudolocalization

## Example prompts
- Organize our locales folder for react-i18next with en-US and es-MX fallbacks
- Convert these card layout styles to CSS logical properties for RTL support
- Format product prices and publication dates using Intl for Japanese and German locales

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 52ce2f28731febe1.

BEGIN THIRD-PARTY FILE 52ce2f28731febe1
````text
---
name: localization-l10n
description: Implement localization (l10n) best practices to adapt applications for specific regions, languages, and cultural preferences.
metadata:
  maintainer: Mindrally
  source: https://github.com/Mindrally/skills
---

# 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

## Translation Management

### File Organization
```
locales/
  en-US/
    common.json
    legal.json
    marketing.json
  en-GB/
    common.json
    legal.json
    marketing.json
  es-ES/
    common.json
    legal.json
    marketing.json
  es-MX/
    common.json
    legal.json
    marketing.json
```

### Regional Variants
- Support regional language variants (en-US vs en-GB, es-ES vs es-MX)
- Implement fallback chains (es-MX -> es -> en)
- Handle spelling differences (color vs colour)
- Adapt terminology for regional preferences

## Locale-Specific Formatting

### Date and Time Formatting
```typescript
// Format dates according to locale
const formatDate = (date: Date, locale: string) => {
  return new Intl.DateTimeFormat(locale, {
    year: 'numeric',
    month: 'long',
    day: 'numeric'
  }).format(date);
};

// US: January 23, 2026
// UK: 23 January 2026
// Germany: 23. Januar 2026
```

### Number Formatting
```typescript
// Format numbers according to locale
const formatNumber = (num: number, locale: string) => {
  return new Intl.NumberFormat(locale).format(num);
};

// US: 1,234,567.89
// Germany: 1.234.567,89
// France: 1 234 567,89
```

### Currency Formatting
```typescript
// Format currency according to locale
const formatCurrency = (amount: number, locale: string, currency: string) => {
  return new Intl.NumberFormat(locale, {
    style: 'currency',
    currency: currency
  }).format(amount);
};

// US/USD: $1,234.56
// Germany/EUR: 1.234,56 EUR
// Japan/JPY: JPY 1,235
```

## Cultural Adaptation

### Content Localization
- Adapt imagery for cultural appropriateness
````
END THIRD-PARTY FILE 52ce2f28731febe1

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