AssetDropKit

Kotlin Multiplatform asset packs, downloaded on first use from the app stores themselves:

Platform	Delivery	Hosted by
Android (minSdk 24)	Play Asset Delivery, on-demand packs	Google Play
iOS 26 and later	Apple-hosted Background Assets	the App Store
iOS 17 and 18	On-Demand Resources	the App Store

The stores host the bytes, so there is no server and no hosting bill. Your app keeps its install size small and fetches a game's art the first time someone plays it.

Quickstart

// commonMain
val packs = AssetPacks(source = source) // PlayAssetPacks on Android, AppleStoreSource on iOS

when (val state = packs.fetch("postdelivery")) {
    PackState.Ready -> {
        val glb = packs.readBytes("postdelivery", "town/sedan.glb")
    }
    is PackState.Failed -> showOfflineFallback(state.reason)
    else -> askTheUser() // WaitingForWifi or NeedsPlayConfirmation, Android only
}

packs.state("postdelivery").collect { state -> showProgress(state) }

• Two callers fetching the same pack share one store request.
• Every pack is checked against its assetdropkit.json once per version; a changed or missing file removes the pack, fetches it once more, then reports Failed(Corrupt).
• readBytes runs on the dispatcher you inject (default Dispatchers.Default), never on the caller's thread.
• After a relaunch, the first state comes from the store, so a download that was running shows as running; a store's Ready becomes Ready only once the pack matches its manifest.
• stallTimeoutMillis turns a download that stops moving (offline, parked in Pending) into Failed(NoNetwork).

Install

// shared module
commonMain.dependencies { api("com.vocabloot:assetdropkit:0.1.1") }
commonTest.dependencies { implementation("com.vocabloot:assetdropkit-test:0.1.1") }

The Apple side is a Swift package: add https://github.com/vaazh-studios/assetdropkit in Xcode. Then follow Android, iOS and Packaging.