App Thinning

App Thinning is a set of Apple technologies that optimize iOS app delivery by ensuring each device downloads only the resources it needs. Instead of distributing a universal binary with assets for every supported model, App Thinning creates tailored variants that shrink download size, installation footprint, and storage usage.

Three Components of App Thinning

App Thinning consists of three technologies. Slicing creates device-specific variants at the App Store level, including only the executable architecture, GPU resources, and image assets the target device requires. Bitcode let Apple recompile and optimize your binary for specific hardware after submission, though Apple deprecated it in Xcode 14. On-Demand Resources let developers tag assets for download only when needed and purge them when storage runs low, a feature especially useful for games and content-heavy apps.

Why App Size Matters for ASO

Download size directly affects conversion rates. Apple enforces a 200 MB cellular download limit; apps above that threshold require Wi-Fi, creating friction that cuts impulse installs. Smaller apps also launch faster, lowering abandonment. Users with limited storage tend to delete large apps, hurting retention. By leveraging App Thinning, developers keep download size below critical thresholds and strengthen both conversion and long-term retention.