During February’s market correction, Betterment was among several online investing sites that temporarily went offline, overwhelmed by high visitor volumes.

Even though the digital advice firm prides itself on the technology stack it has built, there was room to improve. So it added Auto Scaling, an Amazon Web Services application that monitors traffic and then automatically spins up additional capacity in order to keep the website at steady state, says Anil Beniwal, director of engineering at Betterment.

Now, when a sudden spike in traffic occurs, Beniwal says the site will gear up within three minutes, instead of half an hour.

Other wealth management firms are also turning to Amazon’s cloud computing platform, even as Amazon itself inches closer to entering the financial services industry.

Vanguard has been moving key operations to the AWS cloud, pivoting from an in-house private cloud, said Jeffrey Dowds, chief technology officer in information technology and security at Vanguard. Dowds explained the company was attracted to AWS’ advanced applications, such as analytics and machine learning capabilities.

“The way you can tell you are doing something serious at AWS is take a look at your bill,” said Dowds, whose comments drew a few gasps from the audience attending the Amazon Web Services Financial Services Cloud Symposium conference held in New York on Wednesday. “We had a bill that was zero, two-and-a-half years ago. And now we have a bill that we measure in the millions.”

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AWS is a highly profitable part of the Amazon empire and has seen revenue increase by 49% in the first quarter of this year, with sales at $5.44 billion. The cloud computing platform takes up 73% of Amazon's operating income, which is $1.93 billion.

Firms subscribing to AWS are offered over 125 services to customize their operations, noted Amazon Web Services CEO Andy Jassy, who name dropped clients such as FINRA and Nasdaq.

“We have functionality, more than anybody else,” he claims. “Do what you need. If it turns out you need more, you seamlessly scale up. If it turns out you need less, you give it back to us.”

The platform continues to make inroads into banks and wealth management firms, said Phil Moyer, director of financial services at AWS.

"Having a global infrastructure and having access to a global infrastructure for an organization like Betterment or Robinhood or Fidelity or Vanguard, first and foremost, you get this incredible capability in a worldwide basis," Moyer said.

That global infrastructure is not foolproof, however. Last year, some AWS servers went down due to an incorrectly entered command. As a result websites including Quora and Trello went dark.

Still, the power of the AWS cloud applications and conversational technology of Alexa have made fintech analysts take notice and speculate about Amazon’s intentions, especially after news leaked that it is seeking a banking partner, possibly JPMorgan Chase and Capital One, for a checking account-like product for millennials.

"I think it's pretty unlikely we will be a competitor for financial services companies. I have been at Amazon for 21 years and I've learned never say never about anything. We can't do all the businesses that exist in the world,” Jassy said.

As for concerns about Amazon being a future competitor in the wealth management space, Joe Ziemer, vice president of communications at Betterment, pointed out its connection with Vanguard, which has digital advice platform Personal Advisor Services.

“We’ll continue to choose the best service provider in each facet of our business where we utilize a third party that helps deliver the best possible customer experience,” Ziemer said. “For example, we continue to utilize Vanguard ETFs even though they have a product that is perceived as competitive.”

Sharon Adarlo

Sharon Adarlo is a Financial Planning contributing writer in Newark, New Jersey. She has also written for The Wall Street Journal and about science and engineering for Princeton University. Follow her on Twitter at @sharonadarlo1.