In an increasingly globalized digital landscape, mobile apps must cater to diverse audiences. For iOS apps, localization is more than just translation – it’s about delivering a seamless, native-like experience for users worldwide. However, while Apple provides a structured approach to iOS localization, challenges remain. From managing Xcode’s .xliff files to updating translations without App Store resubmissions, developers must navigate multiple hurdles.
This guide explores
- iOS localization best practices,
- the role of iOS over-the-air (OTA) updates,
- a step-by-step iOS app localization tutorial
- Common pitfalls, and iOS localization best practices
Key Business Benefits of iOS Localization
- Higher conversion rates: Studies show that users are 72% more likely to engage with content in their native language.
- Improved retention: Localized apps reduce churn rates by 30-40% compared to English-only versions.
- Better App Store rankings: Apple’s App Store Optimization (ASO) factors in localized keywords, boosting visibility in different regions.
- Competitive advantage: While most apps focus on English and a few major languages, supporting regional languages can unlock untapped user segments.
Understanding iOS Localization: How It Works
Apple provides built-in localization tools within Xcode that allow developers to separate text-based content from code, making it easier to support multiple languages. The traditional process includes:
- Extracting localizable strings: Developers use .strings files to store translatable text separately.
- Using Xcode’s export feature: Xcode allows exporting all localizable strings into an .xliff file for translators.
- Reintegrating translations: The translated .xliff file is re-imported into Xcode, updating the app’s text content.
Challenges in Traditional iOS Localization
- App updates required for every translation change: Even minor fixes require a full app update, slowing down iteration.
- Manual file handling: Managing .xliff files manually increases the risk of missing translations and version conflicts.
- Lack of real-time updates: If a business needs to update its UI text due to seasonal campaigns or regulatory changes, the traditional approach doesn’t offer agility.
Reverie’s Anuvadak overcomes these limitations by seamlessly combining static and dynamic localization – ensuring every part of your app is instantly accessible in multiple languages.
iOS Dual Layer iOS Localization Approach
To deliver a fully localized user experience, iOS apps require both
- Static content localization (Anuvadak OTA SDK)
- Dynamic content localization (Anuvadak API for Server-Fetched Content)
Below is a pictorial representation of how Anuvadak’s OTA localization process operates.
Static iOS Over-the-Air (OTA) Localization
Traditionally, updating static content like navigation text, labels, or menu items meant resubmitting the app for approval – a tedious and time-consuming process. Anuvadak’s OTA SDK changes this.
How it works
- Modify static content instantly using Anuvadak’s web editor.
- When users launch the app, the OTA SDK fetches the latest localization data automatically.
This ensures that UI content updates – from typo corrections to terminology changes – are reflected immediately.
Dynamic Content Localization (Anuvadak API for Server-Fetched Content)
For content that changes frequently, like BFSI, e-commerce product details, news articles, or user-generated text, static localization isn’t enough. Anuvadak’s API-driven localization ensures that this content is translated in real time, eliminating the need for pre-stored .strings files.
How it works
- Fetch content dynamically from the backend.
- Call Anuvadak’s API to retrieve translations instantly.
- Render localized content in the app without requiring additional updates.
This ensures users always see content in their preferred language – whether it’s static UI text or live, dynamic data.
Step-by-Step iOS App Localization Tutorial
Note:
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Setting up your iOS Project for Localization
Before you start translating, ensure the following action/ something is set up correctly, that is :
- Integration:
- Embed the iOS localization tool framework provided by Reverie into your project by signing up.
- Provide yourself with a proper Reverie’s Web and iOS localization tool – Anuvadak Project app ID to use the SDK.
- Setting up your app:
- “Localizable.strings” stores application strings as key-value pairs for each language. Let’s create this file for the base language first.
- Select File → New → File or just tap Ctrl+N or Cmd+N.
- Search for strings, and Select “Strings File” in the “Resource window”:
- Locate and select the “Localizable.strings” file in the Navigator panel.
- Navigate to the Utilities panel.
- In the Localization section, click on “Create” to enable localization for the file.
- Follow the on-screen instructions to continue with the localization setup.
- Adding languages by creating .strings files for each language.
- Select your root project file.
- Proceed to the project panel to access project settings.
- In the Localization section, click the plus (+) icon and add the desired languages.
- Choose only the Localizable.strings file for localization
- Working with translations
- The iOS App localization process involves “keys and values”.
- Key is a unique identifier that is used in the source code; when the application is served to the user, keys are replaced with the corresponding translations for the language set by the user. Let’s add two entries into the .strings files for English translation.
- Localizable.strings (English):
“welcome_screen_title” = “Welcome”;
“login_button” = “Log in”;
Once the keys are set up, the next step is retrieving translations. At Reverie, we offer two integration methods:
- UIKit Integration
- Swift Integration
As an industry leader in next-generation language solutions, we have extensively worked across these technologies. While many solutions claim to offer quick implementation, our Swift integration method has been rigorously tested by our clients, ensuring a seamless and efficient localization process that is even simpler than expected.
Below is a detailed guide on implementing iOS localization using the traditional UIKit approach. If you’re interested in learning more about Swift integration, feel free to reach out to us or stay tuned to our latest blogs, where we share in-depth insights and updates on localization technology.
Uikit Integration
- Initializing the SDK
- Updating the Locale on Runtime
- Receive localisation Complete Status
- Updating UI
- Other Integration Support
1.1 Initializing the iOS localization tool SDK
Initialize the Function with bundle swizzling (necessary for storyboard localization) in the AppDelegate class with initLangify function
Note :
- initAnuvadak function will change the Locale with translated string in app Startup
- enableBundleSwizzling is required for using by default NsLocalisedString and storyboard localization
import AnuvadakSDK
@main
class AppDelegate: UIResponder, UIApplicationDelegate {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
Log.VERBOSE = true
AnuvadakManager.sharedInstance.enableBundleSwizzling() //Required for storyboard localisation
AnuvadakManager.sharedInstance.initAnuvadak(appId: “app-ID”, currentLocale:String(Bundle.main.preferredLocalizations[0].prefix(2) ))
return true
}
1.2 Updating the Locale on Runtime
You can also Update the Locale(language) in the Runtime of the app using our SDK
UserDefaults.standard.set(“hi”, forKey: “AppleLanguages”)
UserDefaults.standard.synchronize() AnuvadakManager.sharedInstance.updateLocale(lang:locale )
1.3 Receive localisation Complete Status
You can update the UI using the Callback Function when localization is being applied.
class ViewController: UIViewController , AnuvadakNotifyUpdate{
func onError(message: String) {
print(message)
}
func onUpdated(isTrue: Bool) {
updateView() // or refresh the Ui
}
func onStartLocalization(isTrue: Bool) {
}
//for using the callback set the delegate for to receive callback
AnuvadakManager.sharedInstance.setNotifyChangeDelegate(notifyChange: self)
You can also update using Notification Observer in the iOS localization tool
NotificationCenter.default.addObserver(self, selector: #selector(updateView), name: Notification.Name(“AnuvadakUpdate”), object: nil)
1.4 Updating UI
In iOS SDK updating of UI is not handled by SDK the Developer has to refresh the UI once he receives onUpdate delegate callback or Notification of update.
Note: Updating the Ui will mostly be used when there is a fresh install in the device to fetch data or a new update of string translation is present in Anuvadak or in .strings file and even in a new language switch
After first time data fetch during the fresh Install or new locale change strings data is stored and appended as soon the application launches .
Also the updating UI is required for the view / page which is currently displayed(or initialized) for rest of the views it would be updated as you navigate to it or view is displayed
Few Examples how Ui can be updated
Example – 1
You can just reinitialize the text field in the iOS localization tool with NsLocalizedString (Swizzling should be enabled before initialization) in this case storyboard based update won’t work in runtime
func updateView()
{
textView1.text = NSLocalizedString(“key1”, value: “”, comment: “”)
textView2.text =String.localizedStringWithFormat(NSLocalizedString(“grape”, comment: “”),2)
button.setTitle(NSLocalizedString(“button”, comment: “” ), for: .normal)
}
Example – 2
If you don’t want to enable bundle swizzling you can use our Custom String Extension in iOS localization tool to get localized string according to the locale you can use it in the following way storyboard localization won’t be updated in this
func updateView()
{
textView1.text = “key1”.Localized(table: “Localizable”)
textView2.text = String.localizedPluralString(numberOfItems: 2, item: “grape”)
button.setTitle(“button”.Localized(table: “Localizable”), for: .normal)
}
Example -3
For updating the StoryBoard based localisation (Bundle Swizzling should be enabled) you the refresh the particular view or the StoryBoard
Refreshing the View/ViewController in the iOS localization tool will allow you to create a custom Extension. In this case you need to refresh any internal views present in the views too
@objc extension UIViewController {
@objc func reloadView() {
let parent = view.superview
view.removeFromSuperview()
view = nil
parent?.addSubview(view) // This line causes the view to be reloaded
}
}
This is For Custom Views Present inside viewcontroller
init() {
super.init(frame: .zero)
setupApearance()
addSubviews()
configureLayout()
NotificationCenter.default.addObserver(self, selector: #selector(reloadView), name: Notification.Name(“AnuvadakUpdate”), object: nil)
}
//Reinitialise the views or the textfields as per the Use Case
@objc func reloadView()
{ setupApearance()
addSubviews()
configureLayout() }
// or refresh
@objc func refresh()
{ let parent = view.superview
view.removeFromSuperview()
view = nil
parent?.addSubview(view) }
-or
You can refresh the whole story board as below
@objc func reloadAppInterface() {
guard let sceneDelegate = UIApplication.shared.connectedScenes.first?.delegate as? SceneDelegate,
let window = sceneDelegate.window else {
return
}
// Assuming your initial view controller is a UINavigationController
let storyboard = UIStoryboard(name: “Main”, bundle: nil)
window.rootViewController = storyboard.instantiateInitialViewController()
UIView.transition(with: window, duration: 0.5, options: [.transitionCrossDissolve], animations: {
window.makeKeyAndVisible()
}, completion: nil) } }
1.5 : Other Integration Support
We provide support through both wrapper-based integration and server-to-server integration, ensuring flexibility based on business needs. At Reverie, our goal is to simplify the entire localization process for our end customers, enabling seamless implementation with minimal effort.
iOS Localization Supported Language codes:
Please find the our IOS Localization supported language codes below:
Language | Language Code | Language | Language Code |
Hindi | hi | Assamese | as |
Odia | or | Bengali | bn |
Punjabi | pa | Gujarati | gu |
Tamil | ta | Kannada | kn |
Telugu | te | Malayalam | ml |
Urdu | ur | Marathi | mr |
iOS Localization Best Practices
- Always test on real devices – Simulators may not reflect actual localization behavior.
- Leverage Apple’s auto layout – Ensures text adapts to different languages.
- Consider Right-to-Left (RTL) support – Use semanticContentAttribute = .forceRightToLeft.
- Automate translations using tools – Tools like Anuvadak SDK streamline translation updates.
- Handle pluralization properly – Use .stringsdict for languages with complex grammar rules.
- Optimize for different character lengths – Some languages expand or contract text significantly.
- Use translation services – Avoid direct machine translation for better accuracy.
Conclusion
Localizing your iOS app is essential for reaching a diverse audience. By using iOS localization tools – like Reverie’s Anuvadak, following this iOS app localization tutorial, and implementing iOS localization best practices, you can enhance user experience and grow your global presence.
Ready to integrate localization seamlessly? Try Anuvadak SDK for automated, over-the-air translations in 23 Indian languages.
Faqs
What is iOS localization and why is it important?
iOS localization is the process of adapting your iOS app for different languages and regions. It goes beyond translation to include formatting, UI changes, and cultural nuances. Proper localization helps increase user engagement, retention, and App Store visibility.
Which iOS localization tool is best for Indian languages?
Reverie’s Anuvadak SDK is a robust iOS localization tool specifically designed for Indian languages, supporting over-the-air updates and both static and dynamic content localization.
Can I update app text without resubmitting to the App Store?
Yes. Using Anuvadak’s OTA SDK, you can push static UI text updates without resubmitting the app, allowing real-time changes and improved agility.
How do I localize dynamic content in iOS apps?
Dynamic content such as product details or user-generated data can be localized in real-time using Anuvadak’s API, ensuring content is always rendered in the user’s preferred language.
What are .strings and .xliff files in iOS localization?
.strings files store translatable text as key-value pairs, while .xliff files are used to export/import translations. Anuvadak simplifies managing these by automating much of the process.
Is there a step-by-step iOS app localization tutorial available?
Yes. This guide offers a comprehensive tutorial on localizing iOS apps using Reverie’s Anuvadak SDK — covering everything from file setup to runtime language switching.
Does Anuvadak support storyboard localization in iOS?
Yes. Storyboard localization is supported through bundle swizzling. Developers can also refresh views or storyboards to reflect language updates dynamically.
What are the best practices for iOS localization?
- Test on real devices.
- Use Apple’s Auto Layout for flexible UI.
- Support RTL languages with semantic attributes.
- Automate updates using localization SDKs.
- Use .stringsdict for pluralization handling.
- Avoid relying solely on machine translations.
How can I update the app language at runtime?
You can update the locale during runtime using AnuvadakManager.sharedInstance.updateLocale(lang:) and refresh the UI to reflect changes immediately.
Which languages does Anuvadak support for iOS localization?
Anuvadak supports 12 Indian languages: Hindi, Assamese, Odia, Bengali, Punjabi, Gujarati, Tamil, Kannada, Telugu, Malayalam, Urdu, and Marathi.
Do I need to create a new .strings file for every language?
Yes. For each language you want to support, create a corresponding Localizable.strings file. Ensure your base language file is in the en.lproj directory.
What’s the difference between static and dynamic localization?
- Static localization refers to UI elements hardcoded into the app (e.g., labels, buttons).
- Dynamic localization covers frequently changing data fetched from the server (e.g., news headlines, product details). Anuvadak supports both.
Can I use UIKit and Swift with Anuvadak?
Yes. Anuvadak supports integration with both UIKit and Swift. You can choose the method that aligns with your app architecture.
How do I handle pluralization in iOS localization?
Use .stringsdict files to define plural forms correctly, especially for languages with complex grammar rules. Anuvadak SDK supports this approach.
Is localization necessary for App Store Optimization (ASO)?
Absolutely. Apple factors in localized keywords during ASO. Localizing metadata and keywords can significantly improve regional discoverability.
