IOTA is transaction settlement and data transfer layer for the Internet of Things (IoT). It's distributed ledger, the Tangle, is based on a data structure referred to as a Directed Acyclic Graph (DAG). In the Tangle there are no blocks or miners, and every transaction on the Iota network must validate two previous transactions through a small proof-of-work (PoW). Thus the more transactions occur, the faster the network can process new transactions, theoretically allowing the network to become more efficient as it scales.