Minka Ledger is a microservice for clearing transactions in multiple currencies using digital signatures. At its core, Minka Ledger is an implementation of the WebWallet API specification, and thus uses IOUs to represent transaction requests, authorize new transaction records and drive all state transitions using digital signatures. IOUs ("I owe you") are digitally signed messages that contain instructions for moving existing balances between accounts, getting new currency units into circulation or configuring parameters in order to implement different currency systems. The purpose of the Minka Ledger API is to verify and keep track of all incoming IOUs in real time in order to compute and serve three basic response types: account balances, transaction history and clearing confirmations.