She thinks she’s figured out What Women Want.

Kate Foster Lengyel is not your stereotypical startup founder. A mother of two young children, Foster Lengyel built a career as a top exec at brands like Juicy Couture and NYDJ, the denim brand that’s a department store favorite. But this past summer, the 40-year-old quit her job as chief marketing officer at the jeans company to create SwearBy, a shopping recommendations app. Launched in beta this month, SwearBy hopes to establish itself as a social network where people go to see which products their friends, uh, “swear by.”

The Brooklyn, N.Y.-based Foster Lengyel was moved to create SwearBy because of frustration at the superficiality of most marketing campaigns. “‘Authenticity’ is the buzzword of the moment, but all the practices we’re employing are the exact opposite of what’s genuine,” she tells Moneyish. One particular peeve was “paying bloggers ridiculous sums to have them talk about their product,” she says. “They’re often not a brand fan and don’t believe in it.”

According to one estimate, brands spent about $500 million on influencer marketing in 2015— a figure that’s expected to grow as high as $10 billion by 2020. But as Foster Lengyel and every other marketer knows, the most effective suggestions are via word-of-mouth. “I felt that all the credible recommendations I got were from a friend over a glass of wine or standing in line at a coffee shop,” the Columbia University MBA says. “But there wasn’t really a place to shepherd word-of-mouth.”

That, of course, is not exactly accurate. Facebook, the largest social network in most developed markets, has a recommendations engine. Yelp Inc. amassed a $3.86 billion market capitalization from amateur dining reviews. “But I’m not necessarily in a shopping state of mind when I’m looking at photos of my friend’s kid on Instagram,” Foster Lengyel says. “I wanted to create a community where such conversations are relevant.”

Foster Lengyel had been seriously considering striking out on her own for about a year before SwearBy’s release. Before quitting, she worked on her project largely on nights and on weekends. “Even within the constructs of a larger corporation, I’ve always been attracted to entrepreneurial roles,” she says, recalling how she’d occasionally spend weekends creating business plans for ideas that she put to one side. “It was now or never.”

Kate Foster Lengyel (SwearBy)

“I don’t look like a typical founder and I’m wide open as to what I’m leaving on the table by walking away,” she adds. “But that experience gives me perspective and will hopefully save me some time.”

Through the app, users can see recommendations made by their Facebook friends and other SwearByers. You can either upload a photo of a product you like or pick one from the app’s database, and briefly describe where you like it. Unlike say Amazon, where three star reviews are de rigeur, Foster Lengyel wants users to only post stuff that they really like. “When we swear, it’s got to be a solemn oath or vow,” she says. “A swear is a six-star [review]. The ‘OMG, this is truly amazing’ gold standard.”

Foster Lengyel won’t disclose how much went into creating the app, but SwearBy hasn’t done any formal fundraising, instead just relying on contributions from family and friends thus far. She plans to monetize the product via affiliate links and “transparent” brand sponsorships. “We want to have fun with the consumer in the retail environment,” she says. “It’s often noisy and confusing and we think we have ways to cut through.”