Coordinator (IOTA)

The Coordinator was a special node operated by the IOTA Foundation that issued signed transactions called milestones at regular intervals; transactions referenced by a milestone were treated as confirmed on IOTA's Tangle, a ledger built as a directed acyclic graph rather than a chain of blocks. It was introduced as a temporary safeguard while the network was small and vulnerable to attack, but it meant one organisation effectively decided which transactions were final. Its weakness was shown in February 2020, when the Foundation stopped the Coordinator after funds were stolen through its Trinity wallet, halting the network for about a month. The Foundation's long-running plan to remove it, nicknamed "Coordicide", culminated in a 2025 mainnet upgrade that replaced it with a staked validator set. Also see Decentralization.