The competition to be the next PayPal is heating up, as a new generation of financial startups races to introduce new features.

Payments processor WePay on Wednesday will unveil a service to make it easier for small businesses to accept payments via bank transfers. That follows a Monday announcement by larger competitor Stripe, which introduced an online “button” to help retailers accept in-app purchases.

These sorts of new services, while admittedly technical and fairly obscure, are crucial to the accelerating growth--and accelerating competition--of fintech startups. That’s especially true of the payments companies that are jockeying with PayPal to handle the ever-growing volume of ecommerce payments.

WePay, No. 62 on the 2015 Inc. 500 list of the fastest-growing private U.S. companies, is betting on a type of technology known as ACH (for Automated Clearing House) payments. That’s the transfer of money directly from one bank account to another, which is cheaper but slower than running a customer’s credit card.

WePay is betting that its new bank transfer option will help it recruit more business from small companies regularly making big-ticket charges--think home remodelers, wedding planners, or photographers whose customers pay them thousands of dollars at once.

“For a certain type of merchant, a credit card doesn’t make sense; it’s too expensive,” says Karen White, WePay’s vice president of product. Credit card fees can run from 2 to 4 percent on average. For its ACH service, WePay is charging 1 percent plus 30 cents per transaction, and that covers “the full spectrum of risk-management” and additional merchant services that WePay’s platform provides to the small businesses that use it to accept digital payments, White says.

The Redwood City, California-based startup was founded in 2008 by college roommates Bill Clerico and Rich Aberman. It posted almost $25 million in revenues last year, and Clerico this summer predicted that WePay could triple that business this year.