Paystack Server side integration for Android

I am a developer my self and I need to integrate paystack in one of my application. I would like to hire someone, who can make server side code and help me implement in on android side. If there is code, they can share me or guide me , I am open to that also. Please make sure you know it well and don't waste time in searching and R&D. I will love to see some sample before I hire you.