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Dynamic feature delivery architecture

A regular feature module is a code boundary. A Play dynamic feature also changes installation/runtime availability.

Delivery choices​

  • install-time: included initially but modularized
  • conditional: installed for device/country/feature conditions
  • on-demand: downloaded when user requests feature
  • removable: eligible for later uninstall where supported

Choose dynamic delivery for meaningful download-size or conditional-capability benefit, not merely because a feature is conceptually separate.

Availability is state​

sealed interface FeatureAvailability {
    data object NotInstalled : FeatureAvailability
    data class Downloading(val percent: Int?) : FeatureAvailability
    data object Installed : FeatureAvailability
    data class Failed(val recoverable: Boolean) : FeatureAvailability
}

UX must handle network loss, storage shortage, cancellation, Play errors, process death during install, update/version mismatch, and user retry. Never navigate by reflection assuming code exists.

Base versus feature dependency direction​

Dynamic feature depends on base. Base cannot directly reference feature implementation classes. Put stable route/capability contracts in base/API module and use supported navigation/registration mechanisms after installation.

Keep shared resources/code in base only when essential; otherwise size savings disappear. Avoid base manifest/class initialization referencing absent feature code.

Data and security​

Downloaded code does not grant authorization. Server and local policy re-check entitlement. Feature should read durable shared data through contracts and handle schema compatibility across app updates.

Testing matrix​

  • fresh install without feature
  • successful/failed/cancelled download
  • background/process death during download
  • installed then app updated
  • low storage/offline/slow network
  • deep link before installation
  • feature removed and requested again
  • bundletool/Play-delivered artifact, not only Android Studio's convenient install
Operational cost

On-demand delivery adds UX states, analytics, support cases, release compatibility, and testing. Quantify initial-size/user benefit before accepting that permanent complexity.

Sources​

Exercises​

  1. Design deep-link flow to an uninstalled AR feature.
  2. Decide which three commerce features should be dynamic.
  3. Plan recovery from process death at 60% download.