NFC bidirectional communication

[Mjones]

According to the thread you linked, unless Particle changed something drastic, the hardware does support it.

Native NFC Support

@Jak, you are correct it seems! From a Nordic DevZone 2017 posting: The nRF52832 and nRF52840 devices have a built-in NFC radio which can be used for exposing data as a dynamic NFC tag (a tag with configurable data). This can be used as a standard tag type for storing a web link or a text, to launch apps on smartphones and tablets as well as for simple and secure BLE pairing (read more here). All these features are provided by the Type 2 Tag library in the nRF5 SDK. Starting from version 12.2…