What is AltStore
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What is AltStore
What is AltStore?
AltStore is a third-party app store that lets you create developer 
certificates to sign unsigned apps and games.
How Does AltStore Work?
 Riley Testut is responsible for developing AltStore, and he made 
use of a feature Apple gives to paid developers. This feature 
allows them to test apps before they put them up for store 
submission, and that means you can sign your own apps.
 Enterprise certificates are not required as they are with other 
similar stores. This feature is why you need to provide your Apple 
ID and is also why only 3 apps can be active on your device at 
any given time. As AltStore is one of those, you can only install 
two more.