How AppCompactor Reduces APK Size Without Breaking Features

Step-by-Step Guide: Using AppCompactor to Trim Your App BundleReducing app size improves download rates, saves users’ storage, and can even boost performance. AppCompactor is a tool designed to shrink Android app bundles and APKs by analyzing contents, removing unused resources, and applying size-optimized transformations. This step-by-step guide walks you through preparing your project, installing AppCompactor, running it safely, and validating results so you can confidently deliver a leaner app.

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What AppCompactor does (brief overview)

AppCompactor examines your app bundle (AAB) or APK and applies a set of optimizations such as:

• Resource pruning (removes unused images, layouts, and other resources).
• Code shrinking assistance (works alongside R8/ProGuard to identify dead code).
• Image recompression and format conversion.
• Splitting or recombining native libraries for optimal packaging.
• Metadata cleanup and manifest optimizations.

Note: AppCompactor is a complementary tool — it should be used in addition to standard build optimizers (R8, ProGuard, bundletool). Always test thoroughly after compaction.

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Before you start — prerequisites and safety

• Java 11+ installed (or the version recommended by AppCompactor).
• Android SDK and build tools set up.
• A project that builds cleanly with your current CI locally.
• A backup of your original AAB/APK and a version control commit you can revert to.
• Ability to run instrumentation and manual tests on target devices/emulators.

Safety checklist

• Keep a copy of the original bundle.
• Run AppCompactor in a staging environment first.
• Use feature flags (if possible) to limit exposure of experimental builds.
• Validate behavior on multiple API levels and device configurations.

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Installation and setup

1. Download and install AppCompactor:

   • If distributed as a CLI jar:

     
     java -jar appcompactor-cli.jar --version 

   • If available via package manager (example):

     
     sdkmanager install appcompactor 

     Follow vendor instructions for your platform.

2. Integrate with your build pipeline (optional):

   • Add AppCompactor as a post-build step in CI to compact artifacts before signing/publishing.
   • For local use, create a script (compact.sh / compact.bat) to run it consistently.

3. Configure AppCompactor settings:

   • Typical configuration options include resource policies, image compression level, code-safety mode, and whitelist/blacklist of assets to preserve.
   • Create a config file (e.g., appcompactor.yml) in your project root. Example keys:
     • preserve-resources: [list]
     • image-quality: 80
     • code-safety: conservative
     • whitelist-classes: [com.example.MyClass]

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Step 1 — Build a clean app bundle or APK

• For AAB:

  
  ./gradlew bundleRelease 

  Result: app-release.aab (or similar)

• For APK:

  
  ./gradlew assembleRelease 

  Result: app-release.apk

Sign or use unsigned artifacts depending on AppCompactor requirements.

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Step 2 — Run AppCompactor (basic)

A simple run might look like:

java -jar appcompactor-cli.jar    --input app-release.aab    --output app-release.compacted.aab    --config appcompactor.yml 

Key flags:

• –input: path to original AAB/APK
• –output: path to write compacted artifact
• –config: optional config to control behavior
• –dry-run: produce a report without modifying the artifact

Start with –dry-run to see what AppCompactor would remove.

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Step 3 — Review the compaction report

AppCompactor produces a report listing:

• Files removed or modified
• Size savings per item
• Risk/confidence levels for each removal
• Recommendations to adjust config (whitelists, thresholds)

Carefully check anything with medium/low confidence before allowing removal (e.g., resources referenced dynamically via reflection or by name strings).

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Step 4 — Adjust configuration and rerun

• If the report shows potentially risky removals, add them to your whitelist.
• If images appear degraded, increase image-quality or exclude certain assets.
• If native libraries are split incorrectly, change library-splitting settings.

Rerun until the report shows acceptable changes. Use the dry-run mode to iterate quickly.

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Step 5 — Test the compacted build

1. Install the compacted APK/AAB on devices/emulators covering:
   • Different Android API levels (minimum, common, newest).
   • Various screen sizes/densities and locales used by your app.
2. Run automated UI/instrumentation tests.
3. Manually exercise features that rely on dynamic resource loading, reflection, or plugin architectures.
4. Monitor logs (logcat) for missing resource or class errors.

If you find regressions, adjust whitelist/config and repeat.

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Step 6 — Signing, distributing, and CI integration

• Sign the compacted artifact with your release key. If AppCompactor requires an unsigned input, sign after compaction.
• Upload AAB to Google Play or distribute APK as you normally would.
• Integrate AppCompactor into CI:
  • Add a stage after build that runs AppCompactor in dry-run mode, stores reports as artifacts, and optionally runs a limited compaction for staging builds.
  • Only compact in release pipeline after approval.

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Troubleshooting common issues

• Missing resources at runtime:

  • Check report for removed files; add to whitelist.
  • Ensure resource names referenced by strings or reflection are preserved.

• Crashes due to removed classes:

  • Increase code-safety mode or integrate with R8 config to preserve entry points.

• Image quality complaints:

  • Raise image-quality or exclude critical images (icons, onboarding screens).

• Increased size after compaction:

  • Some transformations (format conversions, adding metadata) can temporarily increase size; verify with different settings and re-run report.

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Best practices and tips

• Use conservative settings on first runs; tighten progressively.
• Keep an explicit whitelist of resources referenced dynamically.
• Combine AppCompactor with existing tools: R8/ProGuard, bundletool, and Android App Bundle configuration.
• Automate dry-run reporting in CI to track size regressions over time.
• Monitor user feedback and crash reporting closely after release.

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Example appcompactor.yml (simple)

image-quality: 85 code-safety: conservative preserve-resources:   - res/drawable/ic_launcher.png   - res/raw/voice_prompts/ whitelist-classes:   - com.example.analytics.DynamicLoader   - com.example.sdk.ThirdPartyBridge 

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Measuring success

• Compare artifact sizes (before vs after) and record absolute bytes saved and percentage reduction.
• Monitor install/uninstall rates, crash-free users, and performance metrics after release.
• Track CI reports to ensure no regressions in size over time.

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AppCompactor can meaningfully reduce bundle size when used carefully and iteratively. Start with dry runs, use conservative settings, and validate thoroughly across devices to keep user experience intact while reaping storage and distribution benefits.