Near field communication (NFC) is a set of ideas and technology that enables smartphones and other devices to establish radio communication with each other by touching them together or bringing them into proximity, typically a distance of 10 cm (3.9 in) or less. Each full NFC device can work in 3 modes: NFC target (acting like a credential), NFC initiator (as a reader) and NFC peer to peer. Most of the first business models like advertisement tags or other industrial applications have not been successful, always overtaken by another technology (2D barcodes, UHF tags, ...).
The main advantage of NFC is that NFC devices are often cloud connected, "Connected" credentials can be provisioned over the air unlike a standard card (Hotel or visitor applications). All connected NFC enabled smartphones can be provisioned with dedicated apps, which gives any application a huge potential, like dedicated readers (as opposed to the traditional dedicated infrastructure of ticket), access control or payment readers. All NFC peers can connect a third party NFC device with a server for any action or reconfiguration.