The collaboration is part of a trial where BilltoMobile’s list of participating mobile merchants will provide AT&T’s subscribers with access to mobile payments on several digital goods and services sites.

“Mobile payments have always been considered a strong potential competitor in alternative online payments due to the lack of need for pre-registration and the convenience of having all needed data for the payment already memorized and handy, said Jim Greenwell, CEO of BilltoMobile, San Jose, CA.

“The barriers to entry have been high carrier fees and lack of payment platforms and security, which have kept refund rates and customer service calls high,” he said. “Our strategy is to remove these barriers that have stopped mobile payments from becoming a true, competitive, highly adopted alternative online payment option.”

BilltoMobile is an alternative online payment provider.

The company lets merchants use its Direct Mobile Billing service.

This is the second agreement with a major carrier BilltoMobile has announced this year – the company announced a similar integration with Verizon in March.

“We want to be available to as many users as possible,” Mr. Greenwell said. “The combined reach BilltoMobile now has available for the mobile payment option gets us to the threshold that will allow many major online merchants to embrace BilltoMobile as a new payment option.”

BilltoMobile’s service is now available to roughly two-thirds of mobile phone subscribers in the United States – 90 million AT&T subscribers and 93 million Verizon subscribers out of 280 million wireless subscribers in total.

“With any new service comes challenges,” Mr. Greenwell said.  “The main challenge that we will now face is scaling to the rapid growth in transactions we expect.”