🚀 How to Reduce Your React Native APK Size by 70%

#reactnative #android #apk #programming

A large APK size can slow down downloads, increase install drop-offs, and impact user experience — especially in countries with slower internet connections.
In this blog, I'll walk you through practical steps that helped me reduce a React Native app's APK size by 70%! 🔥

📦 1. Remove Unused Assets, Fonts & Libraries

Audit your project and remove unused images, SVGs, fonts, icons, and third-party libraries.
Check if any dependencies are no longer in use, and uninstall them.
Delete unnecessary files to clean up your project.

🎨 2. Compress Images

Use tools like TinyPNG or TinyJPG to compress images without losing visible quality.
Smaller images = smaller APK!

🖼️ 3. Replace PNGs with WebP Format

WebP images are typically 25–30% smaller than PNGs.
You can convert your images to WebP using Android Studio or online converters.
WebP is supported on Android 4.0+ by default.

🔐 4. Enable ProGuard to Minify Code

In your android/app/build.gradle, make sure you enable ProGuard in release builds:

def enableProguardInReleaseBuilds = true

ProGuard shrinks, optimizes, and obfuscates your code by removing unused classes, methods, and fields.
This results in a much smaller APK size.

🛡️ 5. Add an Effective ProGuard Rules File

In your android/app /proguard-rules.pro, add below generics rules.

Here’s a sample ProGuard configuration optimized for React Native apps:

# Add project specific ProGuard rules here.
# By default, the flags in this file are appended to flags specified
# in /usr/local/Cellar/android-sdk/24.3.3/tools/proguard/proguard-android.txt
# You can edit the include path and order by changing the proguardFiles
# directive in build.gradle.
#
# For more details, see
#   http://developer.android.com/guide/developing/tools/proguard.html

# Add any project specific keep options here:
-keep class com.facebook.hermes.** { *; }

# ========== CORE REACT NATIVE ==========
-keep class com.facebook.react.** { *; }
-keep class com.facebook.hermes.** { *; }
-keep class com.facebook.soloader.** { *; }
-keep class com.facebook.jni.** { *; }
-keep class com.facebook.hermes.unicode.** { *; }

# Bridge and native modules
-keep public class * extends com.facebook.react.bridge.NativeModule { *; }
-keep class com.facebook.react.bridge.** { *; }
-keepclassmembers class * { @com.facebook.react.bridge.ReactMethod *; }

# View system
-keep @com.facebook.react.uimanager.annotations.ReactProp class * { *; }
-keep @com.facebook.react.uimanager.annotations.ReactPropGroup class * { *; }
-keep class * extends com.facebook.react.uimanager.ViewManager { *; }
-keep class com.facebook.react.uimanager.** { *; }

# JavaScript and events
-keep class * extends com.facebook.react.bridge.JavaScriptModule { *; }
-keep class * extends com.facebook.react.uimanager.events.Event { *; }

# TurboModules and animation
-keep class com.facebook.react.turbomodule.** { *; }
-keep class com.facebook.react.animated.** { *; }

# ========== THIRD-PARTY LIBRARIES ==========
# React Navigation
-keep class com.swmansion.** { *; }
-dontwarn com.swmansion.**

# Firebase
-keep class io.invertase.firebase.** { *; }
-dontwarn io.invertase.firebase.**
-dontwarn com.google.firebase.**

# Realm
-keep class io.realm.** { *; }
-keep class io.realm.react.** { *; }
-dontwarn io.realm.**

# Async Storage
-keep class com.reactnativecommunity.asyncstorage.** { *; }

# MMKV
-keep class com.reactnativemmkv.** { *; }

# Device Info
-keep class com.learnium.RNDeviceInfo.** { *; }

# Permissions
-keep class com.zoontek.rnpermissions.** { *; }

# Fast Image
-keep class com.dylanvann.fastimage.** { *; }

# SVG
-keep class com.horcrux.svg.** { *; }
-dontwarn com.horcrux.svg.**

# WebView
-keep class com.reactnativecommunity.webview.** { *; }

# Braze
-keep class com.braze.** { *; }
-dontwarn com.braze.**

# ========== NETWORKING ==========
-keepattributes Signature, *Annotation*
-keep class okhttp3.** { *; }
-keep interface okhttp3.** { *; }
-dontwarn okhttp3.**
-dontwarn okio.**

# AWS SDK
-keep class com.amazonaws.** { *; }
-dontwarn com.amazonaws.**

# ========== OPTIMIZATIONS ==========
-optimizations !code/simplification/arithmetic,!code/simplification/cast,!field/*,!class/merging/*
-optimizationpasses 3
-allowaccessmodification
-overloadaggressively
-mergeinterfacesaggressively
-repackageclasses ''
-dontusemixedcaseclassnames
-dontpreverify

# Remove logging
-assumenosideeffects class android.util.Log {
    public static *** d(...);
    public static *** v(...);
    public static *** i(...);
    public static *** w(...);
    public static *** e(...);
}

# Debug info
-keepattributes SourceFile,LineNumberTable
-renamesourcefileattribute SourceFile

✅ This ProGuard configuration ensures that:

Only required React Native classes are kept.
Libraries like FastImage, Glide, and SVG remain functional.
Unused methods and classes are removed to save space.

📱 6. Generate Separate APKs per CPU Architecture

In android/app/build.gradle:

def enableSeparateBuildPerCPUArchitecture = true  

android {  
    splits {  
        abi {  
            reset()  
            enable enableSeparateBuildPerCPUArchitecture  
            include "armeabi-v7a", "arm64-v8a", "x86", "x86_64"  
            universalApk false  # Smaller APKs per device  
        }  
    }  
}

📌 Why? Instead of one fat APK, this generates smaller, device-specific APKs.

🌍 7. Keep Only Necessary Languages

Reduce resource bloat by keeping only supported languages:

android {  
    defaultConfig {  
        resConfigs "en", "fr"  # Only English & French  
    }  
}

⚡ 8. Enable Hermes (Faster & Smaller JS Bundle)

Hermes is React Native’s optimized JS engine—it reduces bundle size and speeds up startup.

In android/app/build.gradle:

project.ext.react = [  
    enableHermes: true  
]

⚙️ 9 Advanced ProGuard Setup

🔐 Enable in android/app/build.gradle

android {
    buildTypes {
        release {
            minifyEnabled true      // Code shrinking
            shrinkResources true   // Removes unused resources
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            crunchPngs true        // Extra PNG compression
            zipAlignEnabled true   // Memory optimization
        }
    }
}

♻️ 10. Native Library Extraction Tweak Big Impact

I noticed a significant size increase after upgrading the app:

• Before upgrade: 112 MB
• After upgrade v0.83: 250 MB

With a simple tweak, I was able to drastically reduce it - the final APK dropped to iust 65 MB

Add the following inside your AndroidManifest . xm] application tag

android:extractNativeLibs="true"

⚠️Important Note

Some community discussions mention that enabling android:extractNativelibs="true" may slightly affect launch performance.

In my case, I thoroughly compared app launch time and runtime behavior before and after applying this change and observed no noticeable performance impact

That said, always test thoroughly on real devices before shipping.

📊 Results

By applying all the above strategies, I was able to reduce the APK size by almost 70%! 🚀
This not only improves the user experience but also positively impacts download rates and app store rankings.

🎯 Final Checklist

Remove unused assets and libraries
Compress images using TinyPNG
Replace PNGs with WebP
Enable ProGuard
Add a solid ProGuard rules file

Hope this guide helps you achieve a super light APK for your React Native app! 🚀
Feel free to share your APK size reduction journey in the comments! 🙌