(Reuters) – Max Levchin, co-founder of online payment giant PayPal, launched a rival business on Tuesday called Affirm that will compete in the crowded but fast-growing mobile payments business.

Affirm’s technology helps shoppers complete online purchases more quickly and easily when they are using smart phones and other mobile devices, according to the firm’s website.

PayPal, owned by eBay Inc, is the leader in online payments, however, the company is being challenged by a host of start-ups, including Square Inc, that focus on new opportunities and problems created by the boom in mobile commerce.

Affirm is focusing on streamlining the mobile checkout process online, which can involve typing

in lots of information, such as an address and card numbers, using a small type pad.

Affirm said it has whittled the online buying process down to two taps on a smart phone screen – one to tap the Affirm button on participating merchant websites and a second to confirm the order.

Affirm is using Facebook Inc to confirm users’ identities, so for first-time users the process includes a third step which involves logging into their Facebook accounts and accepting the Affirm application.

Levchin co-founded PayPal with Peter Thiel and was its Chief Technology Officer for four years, before it was acquired by eBay. He designed and built PayPal’s pioneering online security and fraud-prevention systems.

While PayPal led the way on security, its service has been criticized as not very user-friendly. That has left room for new rivals to develop more consumer-focused payment services.