Android RFID APP

I want to build Android mobile app, and for now I just need to propose the idea and in the attachment the presentation template which I need to fill it out... My question is: Is it possible to build an Android mobile app to track items(e.g. keys) using RFID tags?? I searched about it, and I found NFC which is Tag Writer (may be will help us to build this app and we will need the reader and i think it must be separate chip) To understand the idea of items tracker please check this link: [login to view URL],[login to view URL] Those are tracker app don by Bluetooth tags and I want to know if it's possible to build an app like those but by RFID tags?? Or can you know if one of these app is open source If so, can we build a new app and connected with this app and add some other features and with different interface??