AltStore is an alternative app store for non-jailbroken iOS devices.
AltStore solves the problem of installing third-party applications on iOS without jailbreaking by enabling sideloading of .ipa files using your Apple ID. The approach works by having the iOS app resign applications with your personal development certificate, pass them to a companion macOS desktop application called AltServer, and install them via iTunes WiFi sync. To keep installed apps from expiring, AltStore periodically refreshes them in the background when connected to the same WiFi network as AltServer, and it handles app updates directly through its own interface.
AltStore suits developers and users who want to distribute or install apps outside Apple's App Store ecosystem on standard iOS devices. The project was initially built to distribute the developer's own emulator application but is designed to eventually support anyone listing and distributing apps through the platform. The tool is implemented as straightforward sandboxed applications on both iOS and macOS, relying on standard frameworks like Core Data, Network.framework, and Background App Refresh, making it accessible to developers familiar with conventional iOS and macOS development patterns.
The project maintains a modular architecture split across several components: the main AltStore iOS application handling most functionality, a simpler AltServer macOS counterpart, a shared AltKit framework for common code, an internal AltSign framework for communicating with Apple's servers and app resignation, and an internal Roxas framework for simplifying common iOS development tasks. Development requires Xcode 15 and Swift 5.9, with iOS 14.0 minimum for AltStore and macOS 11.0 for AltServer. The codebase is organized to keep both applications relatively straightforward to compile and run for developers already experienced with iOS or macOS development.
