If your proximity requirement is of the order of few centimeters then NFC probably be a good choice! NFC is still a new technology being adopted in Mobile phones so current install base is limited. Otherwise, if it is of the order of few feet, then the best choice is Bluetooth. But your requirement is quite possible to create such an app using NFC.
However, now to detect NFC tags and read messages that contain NDEF data we should follow the following steps:
In the Apple Developer site, create a new App ID and make sure that NFC Tag Reading is enabled
Setup the .plist file with their suggested Keys, NFCReaderUsageDescription = NFC Tag! and com.apple.developer.nfc.readersession.formats=NDEF
enable Core NFC via the Capabilities tab in Xcode
Add CoreNFC framework
Import CoreNFC header to ViewController
Set the delegate(NFCNDEFReaderSessionDelegate)
Add necessary methods in the delegate callback
Add method to stop the reader
For reading and parsing NFC tag best we use VYNFCKit, an open source NFC NDEF message payload parsing library. It supports parsing almost all data types TagWriter supports, including Business card, Link, WiFi, Email, Telephone number, Geolocation, Plain text, and SMS
Hence, after getting data parsed through VYNFCKit parser, simply we call RESTFull API and send them on the server. So later we can access them.