ios - How do you constantly run in background?

Question

Alarmy (iOS app) has a neat feature that plays alarms even when in background. This is what their FAQ says about it:

Due to Apple's technical policy, applications are not authorized to ring if they are not running in the background. To prevent this, Alarmy is by default configured to constantly run in the background, and this may consume additional battery. You can save battery by going in to our in-app battery-saving mode, but note that in this configuration, alarms will not ring when the phone is in Silent or Do Not Disturb mode!

How can I write an app that can run in the background this way?

Answer 1

See the docs about iOS background modes here.

Mainly there are a few use cases when doing stuff in the background is allowed:

• Apps that play audible content to the user while in the background, such as a music player app
• Apps that record audio content while in the background
• Apps that keep users informed of their location at allntimes, such as a navigation app
• Apps that support Voice over Internet Protocol (VoIP)
• Apps that need to download and process new content regularly
• Apps that receive regular updates from external accessories

I suspect the app you mentioned hacks into one of those categories.