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Android APK Unsigned Build Error Fix

DodaTech Updated 2026-06-24 3 min read

In this tutorial, you'll learn about Android APK Unsigned Build Error Fix. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

Your Android build produces an unsigned APK with APK is not signed or INSTALL_PARSE_FAILED_NO_CERTIFICATES — the APK was built without a signing configuration, preventing installation on devices or upload to Google Play.

Step-by-Step Fix

1. Generate a keystore

# Wrong: no keystore available
# Right: generate a new keystore

keytool -genkey -v \
  -keystore my-release-key.jks \
  -keyalg RSA \
  -keysize 2048 \
  -validity 10000 \
  -alias my-key-alias

Expected output:

Enter keystore password:
Re-enter new password:
What is your first and last name?
  [Unknown]:  John Doe
...
Generating 2,048 bit RSA key pair and self-signed certificate (SHA256withRSA) with a validity of 10,000 days

2. Configure Gradle signing

// android/app/build.gradle
// Wrong: no signing configuration
android {
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

// Right: add signing configuration
android {
    signingConfigs {
        release {
            storeFile file("my-release-key.jks")
            storePassword "your-store-password"
            keyAlias "my-key-alias"
            keyPassword "your-key-password"
        }
    }

    buildTypes {
        release {
            signingConfig signingConfigs.release
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

3. Use environment variables for keystore passwords

// android/app/build.gradle
// More secure: do not hardcode passwords
android {
    signingConfigs {
        release {
            storeFile file(System.getenv("KEYSTORE_PATH") ?: "my-release-key.jks")
            storePassword System.getenv("KEYSTORE_PASSWORD")
            keyAlias System.getenv("KEY_ALIAS") ?: "my-key-alias"
            keyPassword System.getenv("KEY_PASSWORD")
        }
    }
}

# Set environment variables before building
export KEYSTORE_PATH="/path/to/my-release-key.jks"
export KEYSTORE_PASSWORD="your-store-password"
export KEY_ALIAS="my-key-alias"
export KEY_PASSWORD="your-key-password"

# Build the release APK
./gradlew assembleRelease

4. Build the signed APK

# Clean build
./gradlew clean

# Build release APK with signing
./gradlew assembleRelease

# Build Android App Bundle (AAB) for Play Store
./gradlew bundleRelease

5. Verify the APK signature

# Check if the APK is signed
jarsigner -verify -verbose -certs app-release.apk

# Expected output shows "jar verified" with no warnings
# Or use apksigner
/usr/local/android-sdk/build-tools/34.0.0/apksigner verify --verbose app-release.apk

Expected successful output:

Verifies
Verified using v1 scheme (JAR signing): true
Verified using v2 scheme (APK Signature Scheme v2): true
Verified using v3 scheme (APK Signature Scheme v3): true
Number of signers: 1

6. Fix v1/v2 signature scheme issues

// android/app/build.gradle
android {
    signingConfigs {
        release {
            // Ensure both v1 and v2 signing are enabled
            // v1 is required for Android < 7.0
            // v2 is required for Android 7.0+
            enableV1Signing true
            enableV2Signing true
            enableV3Signing true
        }
    }
}

7. Use Android Studio guided signing

# In Android Studio:
# Build > Generate Signed Bundle / APK...
# Select APK or Android App Bundle
# Provide keystore path and credentials
# Select release build variant
# Click Finish

Prevention

  • Keep the keystore file in a secure location and back it up — losing it prevents app updates.
  • Use environment variables or a secrets manager for keystore passwords in CI/CD.
  • Use Android App Bundle (AAB) format for Google Play distribution.
  • Verify APK signature with jarsigner or apksigner after every release build.
  • Test the signed APK on a device with adb install app-release.apk.

Common Mistakes with apk signed

  1. Forgetting deriving (Show, Eq) on custom data types needed for debugging
  2. Placing the wildcard pattern first in case expressions, making all subsequent patterns unreachable
  3. Using head and tail instead of pattern matching, causing runtime errors on empty lists

These mistakes appear frequently in real-world Android code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

Why can't I install an unsigned APK on my device?

Android requires all APKs to be digitally signed before installation. Unsigned APKs will fail with INSTALL_PARSE_FAILED_NO_CERTIFICATES. Sign the APK with a debug or release keystore. |||What is the difference between debug and release signing? Debug signing uses a default debug keystore (created by Android SDK) and is suitable for testing. Release signing requires your own keystore and is required for Google Play distribution. |||Can I reuse the same keystore for multiple apps? Yes, a single keystore can hold multiple keys with different aliases. Use the same keystore but different key aliases for different apps or different products.

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