How to localise your iOS app for international markets — string management, RTL support, date and currency formatting, and App Store localisation.
The App Store operates in over one hundred seventy-five countries with support for forty languages, presenting an enormous opportunity for apps that localise effectively. Localisation goes far beyond translating text strings — it encompasses adapting visual layouts for right-to-left languages, formatting dates, times, currencies, and numbers according to locale conventions, adjusting content and imagery for cultural relevance, and complying with local regulations and data privacy laws. Before investing in localisation, analyse your App Store Connect analytics to identify countries with significant organic interest — if users in Germany, Japan, or Brazil are already downloading your English-language app, those markets represent the highest-return localisation investments. The cost of localising an iOS app varies from five thousand to thirty thousand dollars per language depending on the volume of content, technical complexity, and whether you use professional translation services or community-driven translation.
Xcode's String Catalogs, introduced in Xcode 15, modernise the localisation workflow by replacing the traditional Localizable.strings and stringsdict files with a consolidated, visual editor. String Catalogs automatically discover localisable strings in your SwiftUI code and storyboards, track translation progress per language, support string variations for plurals and device types, and integrate with translation export and import workflows. In SwiftUI, use LocalizedStringKey automatically — any string literal passed to a Text view, Button label, or similar component is automatically localisable. For strings constructed programmatically, use String(localized:) to ensure they are included in the String Catalog. Avoid concatenating localised strings, as word order varies between languages; instead, use string interpolation with positional parameters that translators can reorder. Organise strings into logical tables (files) by feature area to make translation management scalable as your app grows.
Languages vary dramatically in text length and direction, which directly impacts your app's visual layout. German text is typically thirty percent longer than English, while Chinese and Japanese are often more compact. Design your layouts with flexibility using SwiftUI's adaptive layout system: avoid fixed-width containers that will clip or truncate longer translations, use ScrollView for text-heavy content areas, and test your layouts with pseudolocalisation (artificially lengthened strings) during development. Right-to-left language support, required for Arabic, Hebrew, Persian, and Urdu, is largely automatic in SwiftUI — leading and trailing layout modifiers correctly flip for RTL contexts, and most standard UI components adapt their layout direction automatically. However, custom layouts, directional icons (arrows, progress indicators), and asymmetric designs may require explicit RTL adaptations. Use the layoutDirection environment value in SwiftUI to conditionally adjust custom layouts for RTL contexts.
Localising your App Store listing is often more impactful than localising the app itself, because it directly affects discoverability in local App Store search results. A localised app name, subtitle, keyword field, and description enable your app to rank for search terms in each target language. Screenshots should be localised with translated captions and, ideally, content that reflects local usage — using local city names, currency symbols, and culturally relevant imagery. App Store Connect allows you to maintain separate metadata and screenshots for each supported language. For maximum impact, conduct keyword research specific to each target market using local language ASO tools, as direct translation of English keywords rarely captures the actual search terms used by local users. The combination of a localised app with a localised App Store listing typically increases downloads in the target market by two hundred to five hundred percent compared to the English-only version.
Start with three to five languages based on your analytics data showing highest organic interest by country. English, Spanish, Chinese (Simplified), Japanese, and German cover the largest App Store revenue markets. Expand to additional languages based on download data and business opportunity.
Machine translation like Google Translate or DeepL can serve as a starting point but should always be reviewed by native speakers. Incorrect translations in UI labels, error messages, and legal text can confuse users, damage brand perception, and potentially create liability.