IOTA is the distributed ledger project that uses the Tangle data structure.
The Tangle is IOTA’s name for a directed acyclic graph, or DAG, used for transaction settlement and data integrity. Instead of arranging transactions into a conventional linear blockchain of mined blocks, the structure links individual transactions together. When a participant issues a transaction, it is designed to approve two earlier transactions.
This architecture was created with the Internet of Things in mind, where connected devices might exchange small amounts of data or value. IOTA’s design sought to support micropayments without ordinary blockchain transaction fees and without miners competing to package transactions into blocks. The IOTA token is used for value transfers, while the Tangle can also carry data messages.
The name is often confused with other nontraditional ledger projects, especially Nano, because both have discussed alternatives to conventional blockchains. They are not the same system. IOTA’s distinctive structure is the Tangle, while its network design and consensus mechanisms have changed over time, including the Chrysalis upgrade launched in 2021.