Network exposure is a technology to let app developers communicate with their devices or control various aspects of a network. Targeting IoT, Industry 4.0, multi-media streaming, cloud gaming, smart agriculture, smart vehicles, public safety, and also good old telephony.
For example you can subscribe to the event when your battery operated, power restrained device wakes up and gets ready for data communication. Or you may set bandwidth (QoS) for certain communication, and may pay the related fees. Or check calling numbers and block spammers for millions of subscribers instead of managing blocking list on each device one-by-one.
You can combine these API calls with other non-telecom services (mail, calendar, banking, toaster) to come up with your unique app.
This repository contains a couple of basic code snippets, which may let you get started more easily. You may just read standards, like 3GPP TS 29.122 and 29.522. But it is not easy to see what these offer and how to use them. The authors of these examples hope you find them helpful. Have fun.