localization-engineer

name	localization-engineer
description	Framework-agnostic internationalization (i18n) and localization (l10n) patterns for multilingual applications. Covers ICU message format, pluralization rules (CLDR), RTL layout with CSS logical properties, locale negotiation and detection strategies, SEO hreflang tags, cookie/header-based locale resolution, and translation workflow management. Use when adding multi-language support, choosing an i18n library, implementing pluralization or gender-aware messages, formatting dates/numbers/currencies by locale, handling RTL layouts, setting up locale detection, configuring hreflang SEO tags, or managing translation workflows.
license	MIT
metadata	{"author":"oakoss","version":"2.0"}

Localization Engineer

Overview

Provides framework-agnostic patterns for building multilingual applications, covering the full i18n pipeline from locale detection through translation rendering. Addresses universal concerns like ICU message formatting, CLDR plural rules, RTL support, and SEO.

When to use: Adding multi-language support, locale-aware formatting, RTL layouts, pluralization, translation management, locale negotiation, multilingual SEO.

When NOT to use: Single-language apps with no internationalization plans, content that never changes locale, purely server-rendered static sites with no dynamic content.

Key decision: Choose Paraglide for compile-time type safety and minimal bundles in new projects. Choose i18next for broad ecosystem support and incremental adoption in existing projects. See the Library Selection table below.