Two weeks ago, Sarah Eyres, co-owner of Baltimore yarn store Cephalopod Yarns, needed an advance on her small-business loan. She was at a trunk show in Cambridge, Mass., when she discovered that a crucial shipment of yarn — her store’s entire holiday supply — was delayed at the Canadian border. She needed to buy 200 pounds of yarn, enough to last customers a couple of days until the shipment arrived.

So Eyres logged into an iPhone app that let her access the loan, and used a cash advance of about $3,500 to make her purchase. The loan took about seven minutes to complete.

The mobile revolution is beginning to shake up lending, making it far easier to borrow money where and when it is needed. In the past few months, several start-ups and established banks have released smartphone apps, letting users apply for, take out and grant loans.

Eyres uses Kabbage, a site offering loans to small-business owners. In September, Atlanta-based Kabbage released a smartphone app so borrowers can get advances through their iPhones and Android phones, for the same rates they would on their desktops.

Without an app, “I would have just been sitting and waiting for that shipment. I would not have felt comfortable [making the purchase] without the loan,” Eyres said, noting that she doesn’t take her computer with her when she travels.

The smartphone app changes small-business owners’ loan behavior, Kabbage Chief Marketing Officer Victoria Treyger said. “It sort of allows them to get funding on the go and to take advantage of prices.”

It also appears to be tempting people to borrow more impulsively.

Kabbage customers’ average line is for about $23,000, she said, and they typically take seven to nine advances a year when relying on a desktop computer. Based on data from the app’s first few months, Treyger said business owners using the app will likely take several more advances per year — since September, owners have taken out about $1 million on the app.

Other apps, like one released in 2011 by CUNA Mutual, a mutual insurance company in Madison, Wis., let customers apply for loans through their smartphones. Nearly 19 percent of transactions come from mobile devices, according to the company.

Apps for lenders

Another group of apps let individual investors such as Brendan Ross make loans to small business owners on his smartphone. Ross manages Direct Lending Investments, a La Canada, Calif.-based hedge fund investing in peer-to-peer lending platforms, such as, a San Francisco-based online marketplace for lenders and borrowers. On Prosper, borrowers request between $2,000 and $35,000; investors can invest as little as $25.

Prosper’s app — which Ross accesses on his iPad — alerts lenders of available loans every few hours. When he used Prosper’s desktop site before the mobile app was released last year, he found “loans [would] be snapped up,” before he could get to them. Now, he said, “If I see a loan I want to buy, I can buy it ... [It] allows me to act more quickly.

Ross also invests on IOU Central, an online site allowing accredited investors to lend to small-business owners. He signs for loans on his iPad instead of making calls and printing paperwork. “This summer, I was at Northstar in Tahoe. There were $400,000 of loans I wanted to buy, and I bought them in two minutes while my son was putting on his mountain biking [safety] pads.”

Online investment site MicroVentures, released a mobile investment app during a three-day start-up festival in San Francisco in February. The app allowed accredited investors pledge money to promising start-ups from their phones (though it didn’t actually transfer funds). While he thought the convenience of smartphone access would encourage more investment, chief executive Tim Sullivan found that investors weren’t more likely to pledge on their smartphones than they were otherwise. About 3,000 investors pledged $12.8 million on the app, but their actual investments were much less, he said.

“People indicated interest more readily — more people impulsively clicked, ‘I’d like to invest in this company,’ but it didn’t change the actual investment metrics of what we normally saw,” Sullivan said.