IOTA

IOTA is a cryptocurrency, that was specifically developed for the Internet of Things and is based on a directed acyclic graph structure called Tangle, which acts as a blockchain. Owing to this technology, there are no fees on the network, and transactions are fast. Moreover, IOTA is highly scalable, allowing users to conduct micro- and nano- transactions. Developer say that this feature is necessary for Internet of Things, because it allows devices to transfer the exact amount of resources on-demand.