Internationalization I18n

Covers the full stack of making your app work in multiple languages, from setting up i18next or React-Intl to handling the tricky stuff like pluralization rules that vary by language, RTL layouts for Arabic and Hebrew, and locale-aware formatting for dates and currencies. Includes references for both frontend (JavaScript/TypeScript) and backend (Python gettext) approaches, plus practical guides on translation workflows and locale detection. The best practices are solid reminders about text expansion and why you shouldn't concatenate translated strings. If you're building anything that needs to support international users beyond just swapping out a few English strings, this gives you the roadmap and gotchas to avoid.

skills.sh installs: 642
GitHub stars: 379
last updated: Aug 21, 2026

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Install

$ npx -y skills add aj-geddes/useful-ai-prompts --skill internationalization-i18n --agent claude-code

Installs into .claude/skills of the current project.

Files

Internationalization (i18n) & Localization

Overview
When to Use
Quick Start
Reference Guides
Best Practices

Overview

Comprehensive guide to implementing internationalization and localization in applications. Covers message translation, pluralization, date/time/number formatting, RTL languages, and integration with popular i18n libraries.

When to Use

Building multi-language applications
Supporting international users
Implementing language switching
Formatting dates, times, and numbers for different locales
Supporting RTL (right-to-left) languages
Extracting and managing translation strings
Implementing pluralization rules
Setting up translation workflows

Quick Start

Minimal working example:

// i18n.ts
import i18next from "i18next";
import Backend from "i18next-http-backend";
import LanguageDetector from "i18next-browser-languagedetector";

await i18next
  .use(Backend)
  .use(LanguageDetector)
  .init({
    fallbackLng: "en",
    debug: process.env.NODE_ENV === "development",

SKILL.md on GitHub