Astro i18n Skill

Purpose

Provides internationalization patterns for lead generation sites targeting multiple markets/languages. Implements URL-based routing (/en/, /de/, /fr/), translation management, SEO optimization with hreflang tags, and RTL support.

Core Rules

URL structure first — /en/, /de/, /fr/ prefixes for SEO and user clarity
Fallback gracefully — Missing translations default to primary language with console warning
hreflang tags — Required on every page for proper language alternates
RTL support — Use logical CSS properties (margin-inline-start) for Arabic/Hebrew
Persist preference — Store user's language choice in localStorage/cookie
Type-safe translations — Use TypeScript for language codes and translation keys
No hardcoded text — All user-facing strings must come from translation files
SEO metadata — Translate title, description, og:locale for each language
Content parity — Each language should have equivalent content structure
Intl API formatting — Use native Intl for dates, numbers, currency per locale

Implementation Overview

Component	Purpose	Location
`languages` config	Define supported locales + metadata	`src/i18n/config.ts`
Translation files	JSON with nested keys	`src/i18n/translations/{lang}.json`
`t()` function	Translation with fallback + params	`src/i18n/utils.ts`
`[lang]/` routes	Dynamic URL segments	`src/pages/[lang]/`
Language switcher	Dropdown component	Component in layout
hreflang tags	SEO language alternates	`<head>` in BaseLayout
Middleware	Optional browser detection	`src/middleware.ts`

Quick Start

Minimal Config

// src/i18n/config.ts
export const languages = {
  en: { name: 'English', code: 'en-GB', dir: 'ltr' },
  de: { name: 'Deutsch', code: 'de-DE', dir: 'ltr' },
} as const;
export const defaultLang = 'en';
export type Lang = keyof typeof languages;

Translation Usage

---
import { t } from '@/i18n/utils';
const lang = getLangFromUrl(Astro.url);
---
<h1>{t(lang, 'hero.title')}</h1>
<p>{t(lang, 'hero.subtitle')}</p>
<button>{t(lang, 'hero.cta')}</button>

Dynamic Route

---
// src/pages/[lang]/index.astro
export function getStaticPaths() {
  return Object.keys(languages).map(lang => ({ params: { lang } }));
}
---

References

Configuration & Setup:

config.md - Language config, translation files, utilities

Routing & URLs:

routing.md - Dynamic routes, redirects, middleware

Components:

components.md - Base layout, language switcher

Content & Collections:

content-collections.md - Multi-language blog posts

Formatting:

formatters.md - Numbers, dates, currency per locale

RTL Support:

rtl-support.md - Arabic/Hebrew layout support

SEO:

seo.md - hreflang, Open Graph, sitemaps

Forbidden

❌ Hardcoded text in components (use t() function)
❌ Missing hreflang tags on pages
❌ Auto-translating without human review
❌ Different URLs for same content without hreflang links
❌ Ignoring RTL requirements for Arabic/Hebrew
❌ Locale in query params (?lang=de) instead of path (/de/)
❌ Using left/right CSS instead of logical properties
❌ Forgetting to translate meta descriptions and titles

astro-i18n