Savings app Digit is pinning its hopes on millennial and Gen Z customers who are storing up funds for a rainy day.

“We serve a pretty diverse population relative to most finance and fintech companies, and the majority of our customers are actually women,” said Vishwas Prabhakara, Digit’s chief operating officer. “In terms of income, they are mostly up and coming. They don’t make hundreds of thousands of dollars yet, on average, but they’re at the early end of their careers and working their way up.”

The app, which launched four years ago, was an early mover among digital personal finance platforms. It automates savings and debt payments on behalf of customers through a proprietary algorithm. The company claims it has helped users save more than $1 billion since its launch in February 2015, and the average customer is saving $2,500 per year through the app.

Digit generates revenue from a subscription model, which Prabhakara touted for its simplicity and transparency. “We want to provide value to our customers that they can feel, and that can be measured in terms of the impact we’re having on them,” he said. “If we can’t do that, then those customers will turn away, and we’ll know that and feel that.” The company charges $2.99 per month after a free 30-day trial.

When asked about Digit’s growth strategy, Prabhakara noted that customers increasingly are asking for more help on debt reduction, long-term investing and bill payment. “For us, the challenge is how to identify the most important things and build them as fast as possible,” he said. “I think the philosophy around that will always be to listen to our customers’ or potential customers’ wants and needs and continue with our ‘set it, forget it’ approach to automation, so we can work in the background on their goals.” However, beyond an automated feature to let customers save and pay off credit card debts, it has no plans to roll out other new features.

In May, Digit rolled out a feature powered by JPMorgan Chase’s real-time payments network that allows users to transfer their savings into their checking accounts within 30 minutes, for a $0.99 fee. Previously, users would wait up to three days after putting in their request for a standard ACH transfer, although that free option is still available. PayPal-owned P2P payments app Venmo similarly lets users pay a 1% fee to move their money to a debit card within 30 minutes.

Prabhakara declined to comment on Digit’s customers numbers, but he said the app is “growing rapidly.” Digit is ranked ninth among free finance apps on Apple‘s App Store, sandwiched between Bank of America‘s mobile banking app, ranked eighth, and Wells Fargo‘s mobile banking app, which rounds out the top 10.

Digit also uses BBVA USA‘s Open Platform, a banking-as-a-service platform through which the bank’s APIs are allowing Digit to pull funds from their customers’ bank account. Customers then can deposit those funds in a pooled savings account managed by BBVA to pay bills or return funds to third-party bank accounts as desired.

Also see: BBVA USA reels in 50k new customers with Open Platform

Prabhakara said Digit operates only in the U.S. right now and will remain primarily focused on the U.S. market for the foreseeable future. He said Digit’s workforce currently is around 50 employees, but the firm is adding new hires weekly.

As digital money management tools like Qapital and Goldman Sachs-owned Clarity Money grow their customer bases and banks add similar features to their mobile apps, Digit’s automated savings tool is no longer a unique offering. When asked whether he is worried about competitors’ efforts to build similar capabilities, Prabhakara said banks aren’t necessarily motivated to do so.

“Ultimately, banks can build things that are somewhat similar to what we’re doing, but often there’s not an incentive for them to do that,” Prabhakara explained. “If we keep our heads down and deliver financial health in an effortless way — with an impact people can feel and that can be measure — it’s going to be hard for larger institutions to keep pace with the types of innovation we’re working on.”

Bob Meara, senior analyst at Celent, has said Digit should have been rendered unnecessary by the banks themselves. As he wrote in a recent blog post:

“I have no beef with Digit. My discomfort is with why Digit exists in the first place. We have apps for saving, apps for spend tracking, apps for P2P payments and apps to tell our friends what we spend on and elicit their reaction. We have credit card apps, crowdfunding apps and, of course, mobile banking apps. Why yet another mono-function app? Because banks are squandering the opportunity!”