[JoshTriplett]

There's an additional point above that which is more important:

> Apps that use a third-party or social login service (such as Facebook Login, Google Sign-In, Sign in with Twitter, Sign In with LinkedIn, Login with Amazon, or WeChat Login) to set up or authenticate the user’s primary account with the app must also offer Sign in with Apple as an equivalent option.

You only have to offer "Sign in with Apple" if you already have third-party login options. It would be completely unreasonable to require adding a third-party login option if you don't already have one. But if you already have third-party login options, having uniformity seems reasonable.

[cma]

> It would be completely unreasonable to require adding a third-party login option if you don't already have one. But if you already have third-party login options, having uniformity seems reasonable.

What if they required the same thing on websites by having their browser engine look for Facebook/Google sign ins and require an Apple one be present before displaying the page?

[jacurtis]

They sort of do...

Not explicitly as you implied. But implicitly it is required. Let me explain.

You own a service that has social authentication with Google, Facebook, Twitter, etc.. You have web, desktop, and mobile apps for this service (or some combination thereof).

Your iOS app now requires you to offer "Sign in with Apple" as an auth provider, because you already offer Google, Facebook, Twitter, etc.. So you add "Sign in With Apple" to your iOS app because Apple requires because of their monopoly for distribution on iOS devices. So you now add Apple auth as an authentication option within the iOS app.

Now what happens if a user signs up in your iOS app with Apple's Auth? How are they going to log in on your website, desktop, Browser extension, or anything else? Well, I guess you now need to add "Sign in with Apple" on those devices too.

Once you offer an auth provider as an option on one device, it must now be offered throughout your platform on all devices or you risk locking users out.

Thus, if you offer social auth for authentication, and you want distribution on at least one iOS device, you are implicitly required to offer Apple Authentication across your entire platform.

And that is the power of Apple's distribution monopoly on iOS.

Oh, and before you think "well we will just boycott iOS" for my platform. Good luck. You won't get very far (in the US at least) without iOS support if you are just starting. Even an established company would struggle to succeed without iOS support. Imagine if Uber just said "Fuck it, no more iOS app". All their iOS users would say "Fuck it, no more Uber then, Lyft here I come".

[the_gipsy]

> Once you offer an auth provider as an option on one device, it must now be offered throughout your platform on all devices or you risk locking users out.

Is it feasible to not do this, and instead tell users to add any one of the existing auth methods to their account in addition to Apple's, if they want to use the app on another OS?

[untog]

That’s covered by the first bullet the OP posted:

- Your app exclusively uses your company’s own account setup and sign-in systems.

[JoshTriplett]

It wasn't obvious from the quote what the alternative case was.