Apple App Store: Difference between revisions

A similar case occurred with the app Fanhouse in 2021.<ref>{{Cite web |last=@jasminericegirl |date=9 Jun 2021 |title=#fuckapple, a thread I cofounded @fanhouseapp 8 months ago to empower creators to monetize their content. We pay creators 90% of earnings. Now, Apple is threatening to remove Fanhouse from the app store unless we give them 30% of creator earnings. This is theft and exploitation. |url=https://x.com/jasminericegirl/status/1402691047940100100 |access-date=16 Mar 2025 |website=[[X]]}}</ref>

[[wikipedia:Just-in-time compilation|JIT]], which stands for Just-In-Time, is a method of code execution where code, instead of being compiled before being distributed (like an EXE), gets compiled into machine code in real time right before being executed. This method of code execution allows for much faster website loading times, faster emulation, faster program execution (with programs written in JavaScript, Python, Lua...) compared to interpreters, which instead translates code into machine code line by line, which is much, much slower. JIT also employs many more optimization techniques meant to improve performance, but all you need to know is that JIT is much faster than an interpreter.

Safari is allowed to use JIT to compile code from any site, same with Apple's [https://apps.apple.com/app/swift-playgrounds/id908519492 Playgrounds] app on iPad. Playgrounds bundles Apple's [[wikipedia:Swift (programming language)|Swift]] compiler, and shares backend code with the version of Playgrounds found in [[wikipedia:Xcode|Xcode]].

Third-party apps like Pythonista (a Python IDE), emulators like Delta and UTM and terminal environments like iSH are not allowed to use JIT, instead having to interpret code, which comes with serious performance degradation and is more computationally expensive, potentially draining more battery.

An example of apps being heavily affected by this restriction is UTM. UTM is a port of [[wikipedia:QEMU|QEMU]] for iOS, iPadOS and MacOS, allowing users to create [[wikipedia:Virtual_machine|VMs]] that can run various OSes, for example Microsoft Windows. The iPhone's hardware capable enough to emulate various modern OSes at full speed, but due to Apple's JIT limitation, the team behind UTM had to create UTM SE (slow edition) that doesn't require JIT, but is nowhere near as fast as UTM with JIT, only being capable of running MS-DOS and derivatives at acceptable speeds. While methods that enable JIT for apps other than Safari and Playgrounds exist (some currently working on iOS 18.5, like [https://apps.apple.com/us/app/stikdebug/id6744045754 StikDebug]), Apple does not allow the use of JIT in notarized apps, meaning that programs that support JIT will have to be sideloaded, which comes with its own set of restrictions.

In the EU, Apple gave web browsers permission to use rendering and JavaScript engines other than the built-in with Apple WebKit/JavaScriptCore, with the option for JS engines to use JIT. The browser still has to be approved by Apple for an entitlement, and then must work within APIs provided by Apple for it. But, as of January 2025, no browsers that use different engines than the built-in ones have been released, mainly due to arbitrarily imposed restrictions, meant to discourage the usage and development of third-party engines.<ref>{{Cite web |title=Mozilla says Apple’s new browser rules are ‘as painful as possible’ for Firefox |url=https://www.theverge.com/2024/1/26/24052067/mozilla-apple-ios-browser-rules-firefox |url-status=live |access-date=16 Mar 2025 |website=[[The Verge]]}}</ref>

 

However, Apple still does not allow different engines outside of the EU, with or without JIT support.<ref>{{Cite web |title=App Review Guidelines |url=https://developer.apple.com/app-store/review/guidelines/#2.5.6 |url-status=live |access-date=16 Mar 2025 |website=[[Apple Developer]]}}</ref>