Methods and apparatus, including computer program products, for transactions associated with a mobile device are discussed. A method can include receiving a merchant identifier, sending an identification data, receiving a transaction, and processing a funds transfer. The receiving the merchant identifier is from a mobile device associated with a user registered with a central payment service. The identification data is associated with the user and the identification data includes multiple identifying data items. The transaction data details a transaction between the merchant and the user. The funds transfer is between the merchant and the user based on the transaction.