NFC NDEF Writer is a free Android application developed by Uri Katsir that allows you to create NDEF compatible NFC tags. With this app, you can easily write your data to an NFC tag and ensure that it is formatted correctly for NDEF compatibility. One of the standout features of this app is the ability to use an optional mimetype to launch a specific application when the tag is read.

It is important to note that in order to use the mimetype value in the reading application, you must include the mimetype element in the reading application's manifest file. The mimetype you use when writing the tag should be used as the value in the manifest file of the application reading the NFC tags. Overall, NFC NDEF Writer is a useful tool for anyone looking to create NDEF compatible NFC tags quickly and easily.