Fintech companies are threatening banks on many fronts, but it is in peer-to-peer payments that banks may be most at risk of being reduced to "dumb pipes."

Banks may not have much time to reverse this trend, observers say. Their edge is their legacy and history with customers — that trust even empowers consumers to use nonbank for payments. But they need to figure out a way to marry that trust with the ease and convenience that their competitors are offering.

"Consumers are comfortable with these services because they know it's not a Facebook or Snapchat that's processing the money, there's a trusted party — the banks — the payment is attached to," said Michael Moeser, director of payments at Javelin Strategy & Research. "Banks need to focus on keeping the consumer engaged with their payments services."

Expect the major bank vendors to make accessibility in their P-to-P payments a priority in the coming year. Meanwhile the payments system backed by several of the largest banks in the United States is hoping to build the momentum it achieved last year by making use of the system more convenient.

"We want to leverage that trust and security that banks already have, and help them move faster in this rapidly evolving marketplace," said Melissa Lowry, head of product and marketing at ClearXchange, the bank-owned payments service. (Last year, ClearXchange was acquired by Early Warning, a risk management firm also owned by several large banks.)

In 2015, the number of ClearXchange registered users rose threefold to 25 million from 7,500 financial institutions.

Customers of banks that are ClearXchange members do not need to sign up; the service is automatically part of their digital banking offering. Lowry said this convenience is a key to spurring further adoption of the network, and why ClearXChange is seeking to add more member banks.

Anyone with a bank account can sign up for and use the service, but those who are customers of registered member banks can transfer money in real time. Ultimately, she said, the goal is to enable real-time payments for all money movement through ClearXChange by the end of this year.

"Overall our vision is a real-time payment network that is highly secure, ubiquitous and easy to use," Lowry said. "She said the network has also added further services as well, such as business-to-consumer and government-to-consumer disbursements."

Money movement was a key battleground in financial services in 2015, one in which traditional institutions found themselves ceding ground on, Moeser said.

"Financial Institutions were slow in offering P-to-P capabilities and therefore found themselves at a disadvantage in 2015," he said.

Moeser said this is because nontraditional entrants, besides offering real-time money movement and minimal fees, also incorporate social aspects into payments. He said services like Facebook Messenger payments, Snapchat's "Snapcash" feature and Venmo — which utilizes a news feed and other aspects of social networks — have made headway by seamlessly integrating digital payments into the social structure.

"These are platforms where you might be chatting with someone and then say 'Let me send you that money I owe for dinner last night,' or you see your friend is going to a game and you send them money and say 'Pick me up a Knicks hat,' " Moeser said. "It's convenient to be able to send money while you're already in that application."

While banks will likely not add a social aspect to their payments offerings, they need to focus on ease and convenience, Moeser said.

Vendors will play a major role in keeping banks relevant in payments, and they say they are looking for ways to streamline their products.

In October, Fiserv began integrating its Popmoney service with other money transfer and bill-pay services it offers as part of its NOW Network to offer a single, holistic payments experience, said Tom Allanson, president of Fiserv's electronics payments division.

"We don't look at P-to-P as just a stand-alone service; we are offering a blended service so consumers can manage their financial lives easier," Allanson said.

FIS is also ramping up the capabilities of its People Pay service, which currently offers real-time payment delivery available today through its own network and via a partnership with PayPal, according to a spokesman for FIS. The company recently launched an "e-gifting" service where consumers can send retailer-branded virtual gift cards through the network.

But, as Javelin's Moeser noted, competing with the social aspect of some of the fintech payments providers will be difficult. In fact, typical Venmo users check in to the app four to five times a week to look at the social feed, even if they don't transfer money, said Adrianne Wright, a spokeswoman for the company. (Venmo was acquired by PayPal in 2013.)

"It's a different type of social network," Wright said. "Our users like the simplicity and organic feel of the service."

Wright said Venmo doesn't see itself as a competitor to banks, but rather "works with them" to help its users send money.