Cloud gaming is shaping up to have a big moment on mobile starting next month with the launch of Microsoft’s xCloud service, but iOS users are getting left out. And now we know exactly why: Apple won’t allow those products, because of strict App Store guidelines that make cloud services like xCloud and its competitor, Google Stadia, effectively impossible to operate on the iPhone.

We already knew that there was some issue, likely App Store-related, as to why Stadia wasn’t available for Apple devices and why Microsoft’s service would likely face a similar fate. It seemed even more likely that xCloud’s fate on iOS was sealed yesterday when Microsoft cut off iOS testing for its xCloud app well ahead of its September 15th launch date on Android. Nvidia’s GeForce Now service is also similarly Android-only when it comes to phones, even though that platform technically lets you access titles you already own.

But Apple has finally come out and said, in a statement to Business Insider, that these kinds of cloud services are in violation of App Store guidelines and cannot, in their current forms, ever exist on iOS. The primary reason: they offer access to apps Apple can’t individually review.

Here’s the official Apple statement:

The App Store was created to be a safe and trusted place for customers to discover and download apps, and a great business opportunity for all developers. Before they go on our store, all apps are reviewed against the same set of guidelines that are intended to protect customers and provide a fair and level playing field to developers.

Our customers enjoy great apps and games from millions of developers, and gaming services can absolutely launch on the App Store as long as they follow the same set of guidelines applicable to all developers, including submitting games individually for review, and appearing in charts and search. In addition to the App Store, developers can choose to reach all iPhone and iPad users over the web through Safari and other browsers on the App Store.

Back in March, Bloomberg reported Apple offering a very similar justification when questioned about potential antitrust issues related to Apple’s Arcade game subscription service, which the company operates despite the headaches its competitors have doing the same.

Photo by Amelia Holowaty Krales / The Verge

Regardless, the key bit in that statement is “including submitting games individually for review, and appearing in charts and search.” The way Stadia works today, and the way xCloud will work next month, is that you pay for access to the service itself, and that service then allows you to pay for or access free games from the cloud. Those games are not stored on a local device in your home, unlike the Apple-approved Valve Steam Link app (although Valve had its own set of troubles getting Steam Link approved on iOS).

So Apple doesn’t know what you’re buying or playing on its devices because it can’t review them beforehand. It also doesn’t see any revenue from these services if they’re simply allowing you to access a subscription service you already pay for, which was the crux of a big showdown between Apple and Basecamp, the creator of new email service Hey, last month, which resolved only when Basecamp compromised with the iPhone maker by adding a free signup option to its iOS app.

Apple is pretty explicit about all of this in the App Store guidelines, specifically section 4.2.7:

4.2.7 Remote Desktop Clients: If your remote desktop app acts as a mirror of specific software or services rather than a generic mirror of the host device, it must comply with the following:

(a) The app must only connect to a user-owned host device that is a personal computer or dedicated game console owned by the user, and both the host device and client must be connected on a local and LAN-based network.

(b) Any software or services appearing in the client are fully executed on the host device, rendered on the screen of the host device, and may not use APIs or platform features beyond what is required to stream the Remote Desktop.

(c) All account creation and management must be initiated from the host device.

(d) The UI appearing on the client does not resemble an iOS or App Store view, does not provide a store-like interface, or include the ability to browse, select, or purchase software not already owned or licensed by the user. For the sake of clarity, transactions taking place within mirrored software do not need to use in-app purchase, provided the transactions are processed on the host device.

(e) Thin clients for cloud-based apps are not appropriate for the App Store.

In other words, unless it’s a full remote desktop app, a cloud gaming service is not allowed as these guidelines are written today — even though very narrowly tailored LAN services like Steam Link and Sony’s PS4 Remote Play are.

Google and Microsoft probably don’t want to offer signup options within the apps themselves because that would mean giving Apple a 30 percent cut of subscription revenue, but apps without “account creation” options violate section (c). Abiding by section (a) is also impossible considering these cloud servers on which the games are running are not owned by and located in the homes of consumers, but placed in data centers far away. And section (e) just flat out says this type of thing — a “thin client for cloud-based app” — can’t exist in the App Store at all; it’s not “appropriate,” Apple says.

There are some workarounds here. For instance, the Shadow cloud gaming service gives you access to a remote computer “host device” that is not technically owned by the user, but rented from the company itself. It’s also not on the same network as the device that’s accessing it. Yet Shadow works, and it’s available on iOS today.

A Shadow spokesperson tells The Verge that, when it found its iOS app was in dispute with Apple earlier this year, it removed the quick launch feature that let users boot right into games. It was then approved, because the app functioned more like a remote desktop service — the “generic mirror of the host device” that Apple mentions as an exception in its App Store guidelines. With Shadow, you still have to go and install Steam, login, and access your existing titles just as you would on any other remote desktop app. But the device users remote into is a gaming PC that Shadow rents to you on a monthly basis, which is a clever way around these restrictions.

Valve did something similar with Steam Link by removing the option to purchase games from the iOS version of the app, as Apple took issue with the fact that Steam Link effectively acted as an app store within the App Store that circumvented Apple’s review processes.

What does all this mean? Well, for now, iOS users are going to be missing out on the mobile-centric cloud gaming wave that’s set to arrive with xCloud’s launch. There is conceivably a way Google, Microsoft, and Nvidia could find ways around this by changing the core functionality of their respective apps.

But it seems unlikely in the short term. The App Store is a massive market so lucrative developers have for years jumped through hoop after hoop to access its nearly 1.5 billion users. In this case, however, there is a fundamental disconnect between how these services operate and the way Apple wants software to function on the iPhone and iPad. That doesn’t seem like it’s going to change any time soon.

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