Mobile device payments

1. A computer-implemented method comprising:

receiving, at a server computing system, a first message from a first device associated with a first identifier of a first user, the first message requesting a payment transaction utilizing first account information associated with the first user and second account information associated with a second user, the first message identifying the second user;

responsive to receiving the first message, identifying, by the server computing system, a second identifier of the second user;

sending, by the server computing system, a second message to a second device associated with the second identifier, the second message requesting the second device to approve the payment transaction, the second message including an approval code, wherein the second device is a mobile device;

receiving, by the server computing system and from the second device, a third message including the approval code;

determining, by the server computing system, that the third message was received within a threshold amount of time; and

based at least in part on the third message from the second device including the approval code:

obtaining, by the server computing system, the first account information associated with the first identifier of the first user;

obtaining, by the server computing system, the second account information associated with the second identifier of the second user; and

processing, by the server computing system, the payment transaction between the first user and the second user utilizing the first account information and the second account information based at least in part on the third message being received within the threshold amount of time.

2. The computer-implemented method as claim 1 recites, wherein the first message is a request to charge the second user.

3. The computer-implemented method as claim 1 recites, wherein the first message is a request to pay the second user.

4. The computer-implemented method as claim 1 recites, wherein the first identifier of the first user is a first mobile phone number and the second identifier of the second user is a second mobile phone number.

5. The computer-implemented method as claim 1 recites, wherein the first message includes at least one of a mobile phone number of the second user, an email address of the second user, or a user identifier of the second user.

6. The computer-implemented method as claim 5 recites, wherein the first message further includes an amount of the payment transaction, and the computer-implemented method further comprises responsive to receiving the first message, parsing, by the server computing system, the first message to identify the second user and the amount of the payment transaction.

7. The computer-implemented method as claim 1 recites, further comprising:

identifying, by the server computing system, the first user based at least in part on the first identifier;

determining, by the server computing system, that the first user and the second user are associated with verified accounts; and

providing the second message to the second device associated with the second identifier of the second user based at least in part on determining that the first user and the second user are associated with verified accounts.

8. The computer-implemented method as claim 1 recites, wherein the payment transaction is a cardless payment transaction and the server computing system processes the cardless payment transaction without (i) reading payment data from a payment instrument of either the first user or the second user at a time of the cardless payment transaction or (ii) receiving input of the payment data at the time of the cardless payment transaction.

9. A server computing system comprising:

one or more processors; and

computer-readable media storing instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising:

receiving a first message from a first device associated with a first identifier of a first user, the first message requesting a payment transaction utilizing first account information associated with the first user and second account information associated with a second user, the first message identifying the second user;

responsive to receiving the first message, identifying a second identifier of the second user;

sending a second message to a second device associated with the second identifier, the second message requesting the second device to approve the payment transaction, the second message including an approval code, wherein the second device is a mobile device;

receiving, from the second device, a third message including the approval code;

determining, by the server computing system, that the third message was received within a threshold amount of time; and

based at least in part on the third message from the second device including the approval code:

obtaining the first account information associated with the first identifier of the first user;

obtaining the second account information associated with the second identifier of the second user; and

processing the payment transaction between the first user and the second user utilizing the first account information and the second account information based at least in part on the third message being received within the threshold amount of time.

10. The server computing system as claim 9 recites, wherein the first message is a request to charge the second user.

11. The server computing system as claim 9 recites, wherein the first message is a request to pay the second user.

12. The server computing system as claim 9 recites, wherein the first identifier of the first user is a first mobile phone number and the second identifier of the second user is a second mobile phone number.

13. The server computing system as claim 9 recites, wherein the first message includes at least one of a mobile phone number of the second user, an email address of the second user, or a user identifier of the second user.

14. The server computing system as claim 13 recites, wherein the first message includes an amount of the payment transaction, and the operations further comprise, responsive to receiving the first message, parsing the first message to identify the second user and the amount of the payment transaction.

15. The server computing system as claim 9 recites, the operations further comprising:

identifying the first user based at least in part on the first identifier;

determining that the first user and the second user are associated with verified accounts; and

providing the second message to the second device associated with the second identifier of the second user based at least in part on determining that the first user and the second user are associated with verified accounts.

16. The server computing system as claim 9 recites, wherein the payment transaction is a cardless payment transaction and the server computing system processes the cardless payment transaction without (i) reading payment data from a payment instrument of either the first user or the second user at a time of the cardless payment transaction or (ii) receiving input of the payment data at the time of the cardless payment transaction.

17. The computer-implemented method as claim 1 recites, further comprising:

receiving user data associated with the second user, wherein the user data is usable to create a user account for the second user, and wherein the user data includes the second identifier;

storing the user account in a datastore associated with the server computing system; and

identifying the second identifier of the second user based at least in part on accessing the user account for the second user.

18. The server computing system as claim 9 recites, the operations further comprising:

receiving user data associated with the second user, wherein the user data is usable to create a user account for the second user, and wherein the user data includes the second identifier;

storing the user account in a datastore associated with the server computing system; and

identifying the second identifier of the second user based at least in part on accessing the user account for the second user.