Online tool for checking if Android APK file is zipaligned and for zipaligning unaligned APK files.
Note: This tool is completely client-based and all processing is done on your device. That means your files are not transferred to the server.
If you you're an Android enthusiast that likes to learn more about Android internals, I highly recommend to check out the Bugjaeger app. It allows you to connect 2 Android devices through USB OTG and perform many of the tasks that are normally only accessible from a developer machine via ADB directly from Android phone/tablet.
Zipaligned Android APK Files
Android APK files are regular zip archive files that contain the application code and various additional resources used by the application.
The files inside of the ZIP archive can be compressed to save space. Some files inside of the APK (ZIP) file are not compressed (e.g. images or other raw resources). These uncompressed files don't need to be extracted and decompressed in memory. Instead they can be directly "memory-mapped" using mmap, which is more memory efficient. This requires that the files start at 4-byte aligned boundaries.
The alignment is usually performed during the last steps of the build process. If you're using regular jar signing (v1 scheme), you should zipalign your APK after signing. In case you're using the newer signing schemes with apksigner, you should zipalign your APK before signing it.
This utility can check if your files are properly aligned and it can also generate properly aligned APK (ZIP) files.
You Want Other features or Something Is Not Working
In case something wasn't working, or you would like this tool to offer some additional features, write directly to my email firstname.lastname@example.org.
I'll try to fix bugs and add requested features if possible.
Other Useful Tools
If you want to get detailed information about Android's APK files, check out my APK Analyzer tool.
Additionally, if you you're an Android enthusiast that likes to learn more about Android internals, I highly recommend to check out the Bugjaeger app. It allows you to connect 2 Android devices through USB OTG and perform many of the tasks that are normally only accessible from a developer machine via ADB directly from Android phone/tablet. I also allows to create backup files and extract data from them.