The payer only needs to enter the amount and a quick note to the recipient (if necessary). The application takes care of identifying the recipient and uses the PayPal Adaptive Payments API to execute the payment on behalf of the payer.
When requesting a payment, the requester fills in the requested amount and an explanation for the request. The payer can approve the payment as-is or alter the amount before sending.
The In Call Payments interface is invoked by a long press on the Search key of the Android phone at any time during a call.
The payer does not need network connectivity (GPRS or WiFi) when sending a payment, communication is done via cryptographically-signed text messages. The payee must have network connectivity in order to verify the cryptographic signature of the text message and claim the payment (instruct the server to execute the payment and debit the payer's account).
Users can choose to either pay a $0.50 transaction fee for each payment sent via In Call Payments or view an ad on the "Send Payment" page. This setting can be changed at any time in the application configuration page.
The application does not require 3G connectivity, it operates over any GSM network. All payment data is exchanged through cryptographically-signed SMS messages.