As women across the country ditched their heels during the pandemic, shoe company Birdies thrived.

The direct-to-consumer brand touts itself as a “stylish flat that’s secretly a slipper.” The result: 300% year-over-year growth in April 2021.

It could have been higher. The San Francisco-based company sold out of all its seasonal fashion items in November, even after purchasing double the amount of slippers in 2020 to meet demand. By the winter holidays, they only had core products available.

“We were never really able to capture the tremendous upside,” said Bianca Gates, Birdies co-founder and CEO. “We learned the hard way that, in our business, you can only sell what you have.”

She declined to share specific sales figures. The shoes range in price from $85 to $140 a pair.

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The idea for Birdies was born when Gates and co-founder Marisa Sharkey, long-time friends from their days in Manhattan, realized they didn’t have a pair of go-to loafers to wear while entertaining friends at home.

“I had this Mr. Rogers’ moment, when he puts on his house shoes,” Gates said.

The pair put their heads together, developed a prototype in 2015 and sold 1,800 pairs to friends and family that year. Gates continued to work her full-time job at Facebook but left in 2017 as Birdies grew, and the founders decided to fundraise.

The brand really took off in 2018 when Meghan Markle was photographed alongside Prince Harry in New Zealand wearing a pair of Birdies flats, causing the shoe to sell out and gain a 30,000-person waiting list.

Since the shoes were already in demand during the pandemic, Birdies didn’t really have to make any big pivots.

Top of mind for the founders were the health and safety of their team, customers and business, Gates said.

“Let’s not do anything radical,” she recalled of their thinking at the time. “Let’s stay in business and play it safe.”

Already engaged with customers over social media, they doubled down — listening to what customers wanted and responding by adjusting their offerings, like manufacturing more slides.

“Being direct-to-consumer allowed us to get data and real time information from customers,” Gates said.

Gates and Sharkey also became more thoughtful about their messaging last year after George Floyd was killed by a Minneapolis police officer.

“We had to do a lot of thinking internally,” Gates recalled. “Do we speak up right now?

“Are we in the business of selling shoes or are we in the business of creating community?” she added.

They also thought about the brand’s objective to uplift women, particularly when Kamala Harris became the nation’s first female vice president. When the company posted on Instagram about Harris’ win being a “monumental day for girls and women everywhere,” it lost thousands of followers. It was also its highest engaged post.

“We took a big step back last year to really realize what the mission of our company means,” Gates said. “We are not just in the business of selling shoes.

“We are in the business of leveraging our platform for good.”

That led the brand to become a sponsor of a women’s soccer team, Los Angeles-based Angel City Football Club, this past March. It’s something Gates said would never have occurred to her in the past.

“Coming out of the pandemic, it seems so obvious,” Gates said.

She is also making sure they don’t have a run on their shoes again.

“We are buying deeper and broader,” she said. “Leaning into comfortable shoes is going to stay for a very long time.”

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Disclosure: NBCUniversal and Comcast Ventures are investors in Acorns.