This is a very simple Android app that allows you to write data to NFC tags with custom mime-types.
You can use this app to prepare your NFC tags to work with your own application.
It is based on this tutorial: http://www.jessechen.net/blog/how-to-nfc-on-the-android-platform/
Min Android version: 4.1
App on the playstore: https://play.google.com/store/apps/details?id=nl.paulus.nfctagwriter