Best Practices for Localization in React Native and Expo(2025)

As mobile apps increasingly serve global audiences, localization has become essential for React Native and Expo developers. A well-localized app not only improves accessibility but also boosts engagement and retention across markets.

This article outlines modern best practices for implementing localization in React Native or Expo projects — with a focus on simplicity, scalability, and developer experience.

Why Localization Matters

Localization is more than translation. It involves:

• Adapting text for local languages
• Formatting dates, currencies, and numbers
• Handling layout changes (e.g., RTL support for Arabic/Hebrew)
• Adjusting UX tone and flow to match regional expectations

Getting localization right from the start can prevent costly rewrites and open your app to a broader user base.

1. Use a Consistent Framework

For most projects, choose one solution and stick with it across the app. Options include:

• i18n-js: Lightweight, works well with Expo.
• react-i18next: Full-featured but may require native setup tweaks.
• expo-localization: Helps detect locale settings, used alongside other libraries.
• AutoLocalise: A zero-config solution that removes the need to manage translation files (ideal for rapid iteration).

Choose based on your team's workflow. For apps with fast-changing UI copy or minimal resources, file-free solutions like AutoLocalise can dramatically simplify setup.

2. Avoid Hardcoding UI Strings

Place all user-facing strings in translation-friendly wrappers from the start—even if your app is initially monolingual.

Instead of:

<Text>Submit</Text>

Use:

<Text>{t("Submit")}</Text>

This habit ensures that your UI remains consistent and ready for future language support.

3. Support Dynamic and Nested Content

Your i18n library should support:

• Interpolation
• Plurals
• Fallbacks

Check that your solution can localize both static and dynamic UI content (e.g., modals, alerts, form validation messages).

4. Handle Right-to-Left (RTL) Layouts

React Native provides built-in support for RTL via:

I18nManager.forceRTL(true);

Best practices:

• Use flexDirection: 'row' instead of hardcoding left/right values.
• Leverage I18nManager.isRTL for conditionally flipping UI.
• Avoid absolute positioning for UI elements sensitive to layout direction.

5. Automate Translation Management

If you're using static JSON files, manage them with a shared platform like:

• Crowdin
• Lokalise
• Phrase
• SimpleLocalize

Alternatively, if you want to skip file management entirely, AutoLocalise lets you:

• Translate UI text on the fly via API
• Cache results for performance
• Skip .json files and keys altogether

Example in React Native:

import { useAutoTranslate } from "react-autolocalise";

const Welcome = () => {
  const { t } = useAutoTranslate();
  return <Text>{t("Welcome to the app")}</Text>;
};

6. Test with Multiple Locales Early

During development:

• Change your device/emulator language settings
• Use expo-localization to programmatically set/test locales
• Mock translations with pseudo-locales like [!!localized!!] to spot missing strings

Early testing catches layout breaks, encoding issues, and untranslated strings before launch.

7. Keep Translation Costs in Mind

For large apps:

• Track unique strings to reduce redundancy
• Reuse similar text where possible ("Sign in" vs. "Log in")
• Use vector-based semantic matching

If using paid APIs like Google Translate or DeepL, this optimization can significantly reduce costs.

Conclusion

Localization in React Native doesn't have to be painful. Whether you're shipping a multilingual app from day one or retrofitting localization into an existing project, these best practices can help you build a scalable, maintainable setup.

If you want a fast way to add localization to your React Native or Expo app without translation files, you might want to explore AutoLocalise.

It’s built to help developers skip the boilerplate and focus on shipping globally-accessible apps with less overhead.