The IOTA was released in November 2015 and its main focus is on Internet-of-Things, especially in smart cities, infrastructure and smart grids, supply chains, transportation and mobility. In addition, IOTA can be the backbone of any P2P transaction settlement, such as online payments or even remittances. Its current main functions are micropayments with no fees and secure data transfer and data anchoring, with good scalability and partition fault tolerance. The total supply is about 2,780 trillion (the exact number is (3 ^ 33-1) / 2 = 2,779, 530, 283, 277, 761), and they are all created in the initial block, without the new coins being mined. Because the supply is so large, the price is very small, so the transaction is in millions of IOTA, ie MIOTA.IOTA is a new type of digital cryptocurrency based on a directed five-ring graph rather than a blockchain, focusing on solving the transaction problem between machine and machine (M2M), which is the IoT problem of the Internet of Things. A blueprint for the future machine economy is built by realizing the payment of no transaction fees between machines and machines. IOTA provides efficient, secure, lightweight, real-time micro-transactions without incurring transaction costs. It is an open source, decentralized digital cryptocurrency designed specifically for the Internet of Things. It is a real-time micro-transaction and can be easily and easily extended.