Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for conducting cardless payment transactions. One of the methods includes receiving, in association with a payment transaction, a message from a customer device that includes data from an optical scan of a code displayed at a merchant point-of-sale. A request to authorize a payment for the payment transaction is received from a merchant computer. Customer and merchant accounts are identified and payment data previously associated with the customer account is accessed. The payment is authorized using the payment data, and notification of authorization is sent to the merchant device or customer device.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for conducting cardless payment transactions. One of the methods includes receiving from a first device of a first user a first message requesting a payment transaction with a second user. Using an identifier of the second user provided by the first device, sending a second message to a second device of the second user requesting approval of the transaction, wherein the second message includes an approval code. A third message is received from the second device. If the third message includes the provided approval code and is received within a threshold amount of time, the payment transaction is processed using account information received in the first message.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for conducting cardless payment transactions. One of the methods includes receiving from a merchant computer an indication of a payment transaction by a user associated with a mobile phone number. A text message is provided to a device associated with the mobile phone number requesting approval for the payment transaction, wherein the message includes an approval code. A message is received from the device associated with the mobile phone number. If the text message from the device associated with the mobile phone number includes the provided approval code, account information associated with the mobile phone number is obtained, authorization for the payment transaction is obtained using the account information, and notification of authorization of the payment transaction is provided to a merchant conducting the payment transaction.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for conducting cardless payment transactions. One of the methods includes receiving from a merchant computer an indication of a payment transaction by a user associated with a mobile phone number. A text message is provided to a device associated with the mobile phone number requesting approval for the payment transaction, wherein the message includes an approval code. A message is received from the device associated with the mobile phone number. If the text message from the device associated with the mobile phone number includes the provided approval code, account information associated with the mobile phone number is obtained, authorization for the payment transaction is obtained using the account information, and notification of authorization of the payment transaction is provided to a merchant conducting the payment transaction.

Abstract: Processing cardless payment transactions is described. In an example, a server system can receive a message from a mobile device of a user that includes a code identifying a merchant and can verify the identities of the merchant and the user based at least in part on account data stored in association with the server system. The server system can provide, to a merchant computer of the merchant, user information associated with the user account and can receive from the merchant computer, a request to authorize the cardless payment transaction. The server system can obtain authorization for the cardless payment transaction using account information associated with the merchant account and/or the user account, and can provide, to the merchant computer, notification of the authorization of the cardless payment transaction.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for conducting cardless payment transactions. One of the methods includes receiving from a merchant computer an indication of a payment transaction by a user associated with a mobile phone number. A text message is provided to a device associated with the mobile phone number requesting approval for the payment transaction, wherein the message includes an approval code. A message is received from the device associated with the mobile phone number. If the text message from the device associated with the mobile phone number includes the provided approval code, account information associated with the mobile phone number is obtained, authorization for the payment transaction is obtained using the account information, and notification of authorization of the payment transaction is provided to a merchant conducting the payment transaction.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for conducting cardless payment transactions. One of the methods includes receiving from a merchant computer an indication of a payment transaction by a user associated with a mobile phone number. A text message is provided to a device associated with the mobile phone number requesting approval for the payment transaction, wherein the message includes an approval code. A message is received from the device associated with the mobile phone number. If the text message from the device associated with the mobile phone number includes the provided approval code, account information associated with the mobile phone number is obtained, authorization for the payment transaction is obtained using the account information, and notification of authorization of the payment transaction is provided to a merchant conducting the payment transaction.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for conducting cardless payment transactions. One of the methods includes receiving from a merchant computer an indication of a payment transaction by a user associated with a mobile phone number. A text message is provided to a device associated with the mobile phone number requesting approval for the payment transaction, wherein the message includes an approval code. A message is received from the device associated with the mobile phone number. If the text message from the device associated with the mobile phone number includes the provided approval code, account information associated with the mobile phone number is obtained, authorization for the payment transaction is obtained using the account information, and notification of authorization of the payment transaction is provided to a merchant conducting the payment transaction.