Tips for Optimizing Proguard Performance

ProGuard is an integral tool for obfuscating, optimizing, and shrinking Android code. Enabling ProGuard is a common step in app builds to reduce APK size and protect against reverse engineering. However, using ProGuard effectively with AppSealing requires some care to ensure it works efficiently without disruptions. There are certain best practices for properly configuring ProGuard and troubleshooting issues. Applying these tips can help optimize ProGuard’s work and maximize benefits.

Start with Conservative Configuration

The default ProGuard configuration is quite conservative, retaining all entry points and logging functionality. Start off with these standard settings instead of overly aggressive custom rules. This minimizes disruption chances. Loosening optimizations for greater savings can be done iteratively later.

Retain public APIs intact.

For library projects, retain classes and members that comprise public APIs untouched. This prevents integration issues for consumers. Obfuscate internal implementation classes separately. Let consumers access clean public interfaces.

Preserve Metadata for Java Reflection

Use -keepattributes Annotation in ProGuard rules to preserve annotations. Retain reflection metadata, like method parameter names, to prevent runtime crashes. Similarly, keep the class attributes required for Gson and Jackson JSON parsing.

Avoid obfuscating Android components.

By default, ProGuard skips obfuscating Android components like Activities, Services, and BroadcastReceivers. This prevents framework issues. Avoid overriding the default behavior without sufficient cause.

Analyze ProGuard Outputs

Review ProGuard outputs like mapping.txt, seeds.txt, usage.txt, and dump.txt for insights into discarded code and remapping. Analyzing outputs helps ensure important app flows are retained. Also track increased processing time and APK reductions.

Enable verbose logging initially.

Use the -verbose flag when first integrating ProGuard to retain detailed logs. Verbose logs provide visibility into the reasons for discarding code. Once the ProGuard configuration stabilizes, this can be removed to reduce build time.

Stability Check with Release Builds

Test with ProGuard enabled for release builds to catch issues early. Debug builds may miss spotting some problems, like missing metadata. Check for crashes or malfunctions to identify if the vital code was incorrectly removed.

Compare Code Coverage

Examine code coverage reports before and after applying ProGuard. Check for any dramatic drops in method coverage. This signals the possible removal of active functionality, deeming the coverage tool incapable of executing those flows.

Analyze stack traces.

In case of bugs or crashes, analyze stack traces with and without ProGuard to isolate the root cause. The presence of obfuscated symbols confirms ProGuard’s role. Compare mappings to rebuild the obfuscated trace.

Ensure consistent builds.

Verify builds are consistent with the same ProGuard configuration across environments and machines. Automated build pipelines should apply identical ProGuard settings across all stages to get reproducible and consistent outputs across builds. This prevents unexpected variances across developer desktops, build servers, and production environments. Standardized ProGuard adoption is key.

Use ProGuard Bugfixes Mindfully.

ProGuard fixes many bugs in each new release. But be cautious before upgrading versions across app releases. Bugfixes can inadvertently introduce regressions too. Evaluate the implications thoroughly and test rigorously before adopting new versions in production. Prefer upgrading ProGuard incrementally between releases unless facing critical issues. Conservative adoption avoids the destabilizing effects of frequent changes.

Add custom rules incrementally.

Start with minimal custom rules and add incrementally later as needed. Wholesale changes are harder to troubleshoot. Adopt a step-wise approach to test the effects of each new set of directives. Isolate rules that cause regressions.

Check for Dead Code Elimination Issues

Overuse of -dontwarn can result in eliminating code prematurely before ensuring a lack of side effects. Monitor for inappropriate dead code removal, which may break app functionality in certain flows.

Use the latest stable ProGuard version.

ProGuard improves continuously, so stay upgraded to get the latest optimizations and compatibility fixes. But don’t switch versions arbitrarily between releases. Avoid introducing changes in ProGuard logic across app versions.

Report bugs and workarounds.

If you face a tricky issue with ProGuard, check stackoverflow and file bugs on GitHub. Many problems have documented solutions. Share bugs and fixes to improve ProGuard for the community.

Customize only where required.

ProGuard works efficiently out of the box for typical apps in most cases. Only customize where you see tangible benefits justified by testing. Avoid premature overoptimization without measurements.

Check for redundant rules.

Review custom rules periodically to remove redundancies and overlaps. ProGuard itself may initially cover directives enforced manually. Eliminate obsolete manual configurations to streamline.

Reproduce Issues in Isolation

To diagnose ProGuard bugs, reproduce them in standalone samples, isolating the problem. Share minimal reproducer projects on GitHub for quicker fix resolution. Help contributors analyze and fix bugs faster.

Maintain ProGuard Configuration with Code

Keep ProGuard configuration under source control along with code for consistent application. Embed in versioned Gradle files or maintain as a separate file to synchronize changes.

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Disable Incrementally During Troubleshooting

Narrow down ProGuard-related problems by switching it off incrementally. Disable optimizations, obfuscation, and shrinking individually to pinpoint the source of issues when troubleshooting.

Balance Obfuscation with Readability

Avoid maximum obfuscation, which makes code incomprehensible. Retain some readable symbols for troubleshooting and support purposes. Balance security with supportability for practicality.

Ensure Consistent Obfuscation Across Builds

ProGuard obfuscates code in a random way. Use the fixed seeds option via -printseeds to generate the same output across builds. This particular case streamlines the troubleshooting process between different versions.

These techniques will help you to be able to configure ProGuard for maximum benefit without being at risk of instability in the build or app functionality. This process ensures that you ship the best APKs safely and without any pitfalls. Disciplined use protocols for ProGuard will ensure its full potential is utilized in your Android applications.


ProGuard is a powerful tool, but you need to invest some time to gain the maximum benefit by learning its integration thoroughly. The key success factor is the gradual increase in aggressiveness and rigorous testing to avoid unpleasant surprises. Automating proguard configuration and analyzing outputs reduces the mistakes made when doing this manually. Regular reviews of rules to remove unneeded rules helps prevent bloat. Troubleshooting in a systematic way by separating the various parts of a system contributes to the identification of the problem. The contribution of fixes and improvements to the community itself creates a self-reinforcing cycle. ProGuard can bring about great improvements in the quality of APKs if adoption is responsible without disruption. The eventual benefits of security, efficiency, and user experience are what make it all worth it.

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