What are NFC’s competitors and alternatives?

Reposted from this response to a question on Quora.

• NFC — A subset of RFID, and as a standard has been widely adopted for contactless payments, public transportation and is integrated in most modern smartphones (although Apple lags behind Android in this regard). It is useful for storing data on passive tags which are activated when put in contact with a reader — so there is no need for a power supply within the NFC tag. It also works at a radio frequency that requires close contact between the tag & the reader. This allows for additional security and control, for instance on a door entry card.
• RFID — Other standards of radio frequency identification tagging are possible outside of NFC, which can allow for proprietary data formats in a closed-loop system. Also, using different frequencies can allow for longer ranges, as commonly used in shipping to track items in a warehouse. RFID RAIN is a standard for interoperability of devices to help enable the ‘internet of things’.
• BLE — Bluetooth Low-Energy, or Beacons, uses another standard wireless protocol found in many portable devices. The data sources require power to transmit their signal to nearby devices, but it allows for a greater range than NFC. There is less standardisation of the data format among these devices, and it is often handled at the software application layer — although devices are working to create standards for using ‘beacons’.
• QR Codes — 2D barcodes which require optical scanning to be read, but are also passive and the cheapest option to print at scale. For consumer use, the drawback is that these are not supported natively by smartphones, and the interaction with apps is slower and clumsier than ‘tapping’ or ‘swiping’
• WiFi, Zigbee, Z-Wave — In home automation, there are wireless protocols that fit in well with the WiFi that is already present in many connected homes. Using one of the standards allows for devices to be recognised by a home automation ‘hub’.
• LiFi, Ultrasonic, Chirpcast, etc. etc. — There are lots of new ‘over the air’ data transmission protocols being devised in research labs and garages across the world — the key things to watch are trends in consumer adoption. NFC is a widely supported standard which is already present in many consumer devices, and there are many reasons to adopt an open standard over a proprietary standard, but that is another discussion.