They have a major outage every couple of years. These don't have as much impact as some other cloud outages because they only affect Apple products, i.e. they're not hosting services for other companies.
Theoretically they offer quite a few; in practice, I think nowhere or almost nowhere I've ever worked has gone for those options (except my own self-published games), instead preferring a custom solution that can be shared with web and android.
You'd probably be affected if you used Sign in with Apple, same as if you used third party sign in with Google, Facebook, Microsoft, or others and their authentication was down.
For mobile - For desktop computers, below 10% even. Given that only 73% of world population is estimated to have internet access in total, that makes it just a small fraction of world population overall
To be perfectly honest with you, I wanted to come here to say that their services (on a good day) aren't very reliable anyway.
I routinely have email issues, file transfer issues (to icloud) and issues accessing their binary notarisation service.
The only thing that works routinely well is Apple Pay, however I think that it's refreshing a key lazily in the background and does not actually need a network connection to work. Good design at least.
So when I saw that they're having an outage, I thought. "All at once this time I guess".
I'll be really open here and say that I applied for an SRE job there out of hatred because whoever is in charge of SRE/Infrastructure Operations at Apple is doing a terrible job (or has terrible circumstances).
I've never had issues at all. I use their consumer offerings (iCloud, Apple Music, Apple TV+, Apple Arcade, etc.) and I've never personally witnessed an outage or problem. I regularly transfer stuff to iCloud from my PC running Linux, and I use the email service with a custom domain that used to live on Google until Google canceled the free tier of small business and also raised prices on the paid tier.
It’s a bit hidden, for example if Apple Music isn’t working it will act as if my device is having an issue with the app playing; it doesn’t look like its a service problem because it hangs and freezes the UI for play- and pretty often I will force my mail to refresh and it will say the imap server is unreachable.
Regardless, these kinds of things tend to be somewhat regional. I’m based in Sweden.
If you live in a region where they operate their own data centers, you will be running on Apple data centers. If not, you're running on a mix of Google Cloud and AWS (IIRC). They used to use Azure as well, but I think that's no longer the case.
In any case, your data is encrypted (by Apple) before being uploaded to Google or AWS, and only Apple has that key. Whatever E2EE encryption you use will be applied on top of that.
Last I checked they were phasing out their own DCs in favor of cloud-provided services. Though it's been a while since I have heard anything about it, so maybe those plans got canceled. It could have also been phasing out those DCs for only the specific services and not all services. My details on the whole thing are fuzzy at best.
As far as I know, everything iCloud and Apple Intelligence runs off of their own data centers if you happen to live "near" one, but you could still be using AWS and/or Google as well.
I live near the Danish Apple data center, and pretty much all my iCloud traffic goes there, with a small fraction (<10%) going to Stockholm, which has both AWS and Google data centers, so I assume they're using both for geographical redundancy (erasure coding)
It gets a bit more fuzzy once you start moving into Movies/Music/TV/Billing/whatever as well as their backend services for the store and monitoring.
1. About 25% of their service revenue is from charging commissions in app store and other 25% of the revenue is Google paying them for search default. Other services include things like insurance (applecare) That's not exactly same type services that most of the people would be thinking about.
2. A lot of their services have less criticality (and it's not a ding at them - it's often very explicit design choice).
3. App store having hiccups or iCloud backups being delayed it's not something that will usually gather enough attention of media.
You might be amazed to know how critical Services are to functioning Apple devices. While they mostly can run offline, there are dozens and dozens of services that Apple runs that modern ecosystems require (like certificate related stuff). Other oddball things related to iCloud, APNS and the private services like iCloud relay are all extremely critical to billions of devices. Thankfully the all mostly fail open (captive portal is particularly tricky). Not saying they are as critical or visible as, say, Google.com going down, but none the less would have a very very large and visible problem if they all did go down suddenly. Thankfully, due to Apple design philosophy, most are totally decentralized and teams are given almost complete autonomy on how services are ran, which makes them a huge confusing mess but also, kind of a feature as Apple generally expects them all to fail in odd ways and the software can generally handle it.
