iPhone App can autolaunch after device boot?

Saw an app called PhoneRecover on the AppStore.

They advertise the following:

PhoneRecover will automatically restart after a reboot on the iPhone 3GS and the iPhone 4 running iOS4.

How is this possible? What APIs are used to auto-launch an app after a boot?

How do I keep apps from running in the background in Swift?

First, go to your project's settings and choose the Capabilities tab. You need to enable the Background Modes capability, then check the box marked Background Fetch. This modifies your app's Info.

It's built into multi-tasking. "Backgrounded" apps are still in background after a reboot. Presumably the app does some work to re-instantiate itself and get its state going again the first time Core Location hits it in the background, but there's no other magic happening here. Any background-aware app will survive a reboot in a backgrounded state.