The most important part of the bitcoin system is a public ledger that records financial transactions in bitcoins. Recording transactions is accomplished without the intermediation of any single, central authority. Instead, multiple intermediaries exist in the form of computer servers running bitcoin software. By connecting over the Internet, these servers form a network that anyone can join. Transactions of the form payer X wants to send Y bitcoins to payee Z are broadcast to this network using readily available software applications. Bitcoin servers can validate these transactions, add them to their copy of the ledger, and then broadcast these ledger additions to other servers.[21]