RFID Reader to phone and server

Need ideas and development... I have multiple Samsung S2 / S3 / S4 / S5 phones that are capable of on-the-go (OTG) connection to an RFID reader. The RFID reader is very similar to a keyboard - it simply captures the RFID code as text in notepad, google sheets etc. I need to capture this RFID code and the exact time when it is read (preferable to the 10th of a second or better (millisecond if possible) if synced to a GPS clock). I will also need to prefix the RFID code with something unique, identifying where this phone is situated (i.e. 1S, 1F, 2S, 2F etc which represents Stage 1 Start, Stage 1 Finish etc) The phone prefix details could be inputted by a user interface. This unique prefix code, RFID code and timestamp then needs to save to the phone (incase of no data connection which can be easily downloaded via bluetooth/cable to a laptop) AND upload to a server. I'm unsure of server type and will take recommendations - I need to feed these timestamps into an already built custom excel spreadsheet that references the uploaded RFID codes to calculate race times, rankings etc Additionally, I would like the mobile phone to 'beep' and the screen to shine green upon RFID scan. This will continue to be a work in progress and will develop over time to meet the needs of the timing system.