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WebCraft Kit
Mobile & Apps Essential

Android strings.xml, iOS Localizable.strings & Flutter ARB Converter

Convert mobile app localization files between Android strings.xml, Apple Localizable.strings, Flutter ARB, JSON, and CSV. Automatically converts format specifiers (%s vs %@) and detects missing translation keys.

Universal Bi-directional conversion: Seamlessly translate between Android strings.xml, iOS Localizable.strings / Localizable.xcstrings, Flutter .arb, JSON, and tabular CSV
Automatic Format Specifier Translation: Intelligently transforms positional arguments (%1$s ↔ %1$@), string tokens (%s ↔ %@), floats (%f), and integers (%d / %ld)
Plural and String-Array Parsing: Converts complex Android <plurals> and <string-array> structures into iOS Localizable.stringsdict and Flutter plural blocks
Diff & Missing Key Audit: Compares base and localized files to flag untranslated keys, mismatched parameters, and orphaned tokens
Special Character Escaping: Automatically handles CDATA, single quote escaping (\' vs '), double quotes, and XML entities (&amp;, &lt;)
100% In-Browser Privacy: All string parsing and regex token transformations execute locally with zero cloud transmission
WebCraftKit Manifesto 100% Client-Side Engine

Air-Gapped Privacy & Zero-Latency Developer Utilities

Every cryptographic algorithm, schema transformer, color space converter, and binary extractor runs entirely in your browser RAM. Your tokens, API secrets, and source code are never sent to external servers.

Zero Server Telemetry
•
Sub-Millisecond Execution
•
70 Production Tools
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Comprehensive Technical Manual

Mobile Internationalization (i18n): Cross-Platform Localization Architecture

In-depth specifications, architectural mechanics, real-world code implementations, and industry best practices.

01

The Mobile Internationalization (i18n) Landscape: Android vs iOS vs Flutter

Cross-platform and multi-repository mobile engineering requires synchronizing localized copy across distinct resource architectures. Android relies on XML resource files located in res/values-[locale]/strings.xml. Apple traditionally uses UTF-8 or UTF-16 key-value pairs in [locale].lproj/Localizable.strings and .stringsdict, expanding to JSON-based String Catalogs (.xcstrings) in Xcode 15+. Flutter utilizes Application Resource Bundle (.arb) files grounded in ICU MessageFormat syntax. Without automated conversion, manual copy-pasting across these formats introduces format specifier mismatches, unescaped character crashes, and missing key defects.

Implementation Example 
// Side-by-side localization format comparison

<!-- Android: res/values/strings.xml -->
<resources>
    <string name="welcome_user">Welcome back, %1$s! You have %2$d messages.</string>
</resources>

/* iOS: en.lproj/Localizable.strings */
"welcome_user" = "Welcome back, %1$@! You have %2$ld messages.";

// Flutter: lib/l10n/app_en.arb
{
  "welcome_user": "Welcome back, {name}! You have {count} messages.",
  "@welcome_user": {
    "description": "User greeting with message count",
    "placeholders": {
      "name": { "type": "String" },
      "count": { "type": "int" }
    }
  }
}
02

Format Specifier Mapping: Deep Dive into Positional Tokens and Data Types

Format specifier translation is the most critical aspect of mobile string conversion. In C/Objective-C/Swift String(format:), object and string variables use %@, whereas Java/Kotlin String.format() on Android uses %s. Positional arguments in Android format (%1$s, %2$d) correspond to Apple positional tokens (%1$@, %2$d). Furthermore, special characters require disparate escaping rules: Android XML requires escaping unquoted apostrophes (\'), ampersands (&amp;), and quotation marks (\"), whereas iOS strings require standard C-style backslash escaping (\").

Implementation Example 
// TypeScript translation engine: Android %s to iOS %@ regex mapper
export function convertAndroidToIosSpecifiers(text: string): string {
  return text
    // Replace positional string specifiers: %1$s -> %1$@
    .replace(/%(\d+)\$s/g, '%$1$@')
    // Replace standalone string specifiers: %s -> %@
    .replace(/%s/g, '%@')
    // Replace Android XML escaped apostrophes: \' -> '
    .replace(/\\'/g, "'")
    // Replace XML entities
    .replace(/&amp;/g, '&')
    .replace(/&lt;/g, '<')
    .replace(/&gt;/g, '>');
}
03

Step-by-Step: Porting an Android strings.xml File to iOS and Flutter

Step 1: Paste your raw Android strings.xml XML payload or upload the .xml file into the input editor. Step 2: Select your target export targets: Apple .strings / .stringsdict, Flutter .arb, or JSON. Step 3: Inspect the real-time conversion output and review the Diagnostics panel for unescaped characters, missing positional arguments, or duplicate keys. Step 4: Toggle plural extraction to generate companion .stringsdict XML blocks for complex quantity rules. Step 5: Click Copy Code or Download Bundle to retrieve ready-to-import localization assets for your Xcode and Flutter projects.

Implementation Example 
// Consuming converted strings in Swift (SwiftUI) & Kotlin (Jetpack Compose)

// 1. SwiftUI (iOS)
Text("welcome_user", tableName: "Localizable")
// Or formatted:
Text(String(localized: "welcome_user"))

// 2. Jetpack Compose (Android)
Text(text = stringResource(id = R.string.welcome_user, "Alex", 5))

// 3. Flutter (Dart)
Text(AppLocalizations.of(context)!.welcome_user('Alex', 5));
04

Automating Multiplatform Localization in CI/CD Pipelines

Enterprise mobile organizations maintain a single source of truth for localization—often managed in Crowdin, Lokalise, Phrase, or a central Git repository containing master JSON files. Integrating automated string conversion scripts into GitHub Actions or GitLab CI guarantees that when product managers update base English strings, native Android XML and iOS strings catalogs are compiled automatically without developer intervention.

Implementation Example 
// Node.js CI script: Convert master JSON into Android strings.xml
import fs from 'node:fs';

function generateStringsXml(jsonPayload: Record<string, string>): string {
  let xml = '<?xml version="1.0" encoding="utf-8"?>\n<resources>\n';
  for (const [key, value] of Object.entries(jsonPayload)) {
    const escaped = value
      .replace(/'/g, "\\'")
      .replace(/&/g, '&amp;')
      .replace(/%@/g, '%s');
    xml += `    <string name="${key}">${escaped}</string>\n`;
  }
  xml += '</resources>\n';
  return xml;
}

const raw = JSON.parse(fs.readFileSync('./locales/en.json', 'utf8'));
fs.writeFileSync('./android/app/src/main/res/values/strings.xml', generateStringsXml(raw));
05

Handling Plurals (stringsdict), RTL Languages (Arabic/Hebrew) & Zero-Leak Security

Languages differ vastly in pluralization rules: English has two forms (one, other), whereas Arabic has six (zero, one, two, few, many, other) and Russian has four. Android <plurals> tags translate directly into Apple .stringsdict XML property lists and Flutter ICU {count, plural, =0{...} one{...} other{...}} blocks. When localizing for Right-to-Left (RTL) languages like Arabic, Persian, or Hebrew, ensure strings do not hardcode directional symbols. All string parsing in WebCraftKit executes 100% in-browser with zero telemetry or server storage.

Knowledge Base & Clarifications

Frequently Asked Questions: Strings Converter

Got questions about how Strings Converter operates, client-side cryptographic safety, or performance limits? Explore common answers below.

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