Mobile payments company BilltoMobile, which now has relationships with all four major carriers in the U.S. (Verizon, AT&T, Sprint and T-Mobile), is today launching one-click processing for mobile web transactions. Previously, users had to enter in their mobile number manually, sometimes a zip code, then wait for a verification code that was sent to their phone through an SMS text. Now, the company says it’s able to identify a user’s mobile number automatically thanks to deeper integration with the carriers’ networks.

The first time a user goes to purchase something via the mobile web using BilltoMobile’s checkout process, they’ll be asked to accept the Carrier’s Terms of Use by way of an opt-in checkbox. They then have to opt in a second time on the same screen to the amount being charged to the phone number BilltoMobile has identified as associated with that device.

Merchants who want to transition their customers to this new checkout process don’t have to make any changes on their end – the same RESTful APIs they used before will now be used to enable this speedier transaction flow.

As for security, BilltoMobile’s payment gateway is tied directly to those belonging to its carrier partners for billing, authentication and customer care purposes. Purchases made through the system then show up on the customer’s next wireless bill, without additional interest charges or subscriber fees. These direct carrier relationships are important to BilltoMobile, as they allow the company to greatly reduce the typical transaction fees than historically ranged from 30%-40%.

The first to use BilltoMobile’s new one-click mobile transaction processing is the social gaming community MocoSpace. Initially, the option will be available on just one, yet to be named carrier partner, but BilltoMobile VP of Sales Paris Leung says the company expects to roll out to the service to the other three top U.S. carriers soon.