Last updated: 10 September 2026
Sphinx is an iPhone app that lets you lock apps you choose and earn time back by solving puzzles. This policy explains exactly what the app does and does not do with information. It is written to be read, not to be skimmed past.
Sphinx does not ask for, receive or store any of the following:
Sphinx contains no analytics or advertising software. It shows no ads. It does not track you across other apps or websites, and it will never ask permission to do so.
This is the part most people want to know about, so it gets its own section.
When you pick apps to lock, you are using Apple's own Screen Time picker. Sphinx never sees your list of installed apps, and it never learns which apps you selected. iOS hands Sphinx an opaque token for each choice — a meaningless identifier that reveals nothing about the app behind it. When you see an app's real icon and name inside Sphinx, iOS is drawing them on Sphinx's behalf. The app itself cannot read them.
These tokens are stored only on your device and are never transmitted anywhere. They are also specific to your device, so they would be meaningless somewhere else even if they were sent, which they are not.
Sphinx keeps the following on your iPhone, in a private storage area shared only between Sphinx and its own Screen Time extensions:
None of this is transmitted, backed up to us, or shared with anyone. There is no server holding a copy, because Sphinx has no server. Deleting the app removes all of it from your device.
The chess puzzles ship inside the app itself, and number puzzles are generated on your device as you play. Solving a puzzle does not contact the internet, and your answers, mistakes and solving times are never sent anywhere.
The chess puzzles come from the Lichess puzzle database, released under Creative Commons Zero. Downloading them was a one-time step during development. The app does not talk to Lichess.
Sphinx is a paid subscription app, and this is the one place where information leaves your device.
Subscriptions are processed by RevenueCat, which manages purchases on Sphinx's behalf. When you subscribe, restore a purchase, or when your subscription renews or expires, RevenueCat receives:
That anonymous identifier is not connected to your name, your email address or your Apple Account, because Sphinx never collects those in the first place. Sphinx uses this information for one purpose: to know whether to unlock the app for you.
Payment is handled entirely by Apple. Your card details go to Apple, never to Sphinx and never to RevenueCat. Sphinx cannot see your payment information. Apple's handling of your purchase is covered by the Apple Privacy Policy.
You can manage or cancel your subscription at any time in Settings › your name › Subscriptions on your iPhone.
Sphinx is not directed at children under 13, and it collects no information that could identify a child. If you are a parent setting Sphinx up on a child's device, nothing about that child is transmitted to Sphinx or to RevenueCat beyond the anonymous subscription information described above.
Deleting everything on your device is as simple as deleting the app. Removing Sphinx removes every lock schedule, preference and puzzle record it stored. Nothing is left behind on a server, because there is no server.
Deleting your subscription record. If you want the anonymous purchase record held by RevenueCat deleted, email the address below and it will be removed. Please note that Apple keeps its own record of your purchase independently, and that deleting the record may prevent you from restoring a subscription you have already paid for.
Depending on where you live, you may have rights to access, correct or delete personal information held about you. Sphinx holds no personal information to access or correct, but if you have a request, the contact address below reaches a real person.
If Sphinx ever changes what it collects, this page will be updated and the date at the top will change. Since the app has no account system, there is no mailing list to notify — the date is the notice.
Questions about this policy, or about privacy in Sphinx generally, go to nguyenlabs10@gmail.com.