In 2012, Jacyln Baumgarten remembered that her happiest childhood memories as a kid involved boating on lakes outside Chicago. Then, within two weeks, her brothers called, each saying he hadn’t used his boat in a year and was going to sell it. Seeing a need--and inspired by the success of platforms like Airbnb--Baumgarten launched peer-to-peer boat-sharing company BoatSetter. (Initially it was called Cruzin; she merged with another company and rebranded in 2015.) The platform allows owners to rent out their boats for a few hours or a few months, thus off-setting the cost of ownership. (Some even come with captains.) Baumgarten’s real innovation was pioneering the first peer-to-peer marine insurance policy, without which boat-sharing would not be possible. The company is speeding forward: this year it has expanded its reach to the Balearic Islands, the Caribbean, the Mediterranean, and Mexico, bringing registered users to over 350,000 in 70 countries. --Hannah Wallace

Finding a contractor is a nightmare, but Cooper Union-trained architect Jean Brownhill knows that the business isn’t broken only for its customers. “General contractors are almost as in the dark as homeowners when it comes to pricing," says Brownhill. "It is an opaque market for everyone.” That’s why, in 2011, she founded Sweeten, a tightly curated platform that helps renovators find contractors, compare prices, and track their project from start to finish. Sweeten is now in four cities and has raised $20 million. Brownhill's target for Sweeten: to serve the top 35 U.S. cities by the end of 2020. And in June she launched the Sweeten Accelerator for Women, which will, among other things, provide a peer network for female general contractors and help them find more jobs. “Three percent of the construction industry is women,” says Brownhill. "It's not that women general contractors can't get hired in this is crazy industry. It’s that male subcontractors don't want to work for them.” --Brit Morse

After an independent stylist asked to rent out a chair in Courtney and Tye Caldwell’s Plano, Texas, salon, the husband-and-wife team knew they had a bead on something valuable. Soon, the Caldwells found themselves helping stylists find empty spaces in salons across the country. For three years, they handled the matchmaking themselves while also meeting the demands of their day jobs--Tye managed the salon and Courtney ran digital marketing strategy for Oracle. In 2015, they automated their side hustle with the ShearShare app. In the four years since, the Caldwells have done a stint at Y-Combinator, raised $1.1 million in funding (with another $2 million anticipated this fall), hired 11 new employees, and expanded bookings to nearly 500 cities across 11 countries. In July, ShearShare debuted a tax assistance feature for self-employed stylists. “We get the ebbs and flows of owning a small business in this industry,” Courtney says. “Our customers stand by us because of that. It’s rare.” --Cameron Albert-Deitch

In 2016, Nicole Carter was spending hours on stock-photo sites, struggling to find images that would resonate with the people her marketing firm was targeting. “I decided, why not contribute to the solution?” she says. She started developing Diversity Photos with her husband, Gerald Carter, and their co-founder, Althea Lawton-Thompson, and launched the following year. The Atlanta-based company works with photographers to provide stock images that represent people of various races, ethnicities, religions, sexualities, sizes, and disabilities. Carter and her co-founders are helping Adobe Stock, Getty Images, and Offset (the premium arm of Shutterstock) make their offerings more diverse. Carter declined to share a revenue figure, but she said that sales have more than doubled in the past year, and Diversity Photos is now profitable. This fall, the company plans to add more photographers to its stable, and is eyeing expansion into video content. --Sophie Downes

Front has been a buzzy company for years now. Silicon Valley’s favorite next-generation version of email, the San Francisco-based startup pulls all your favorite messaging systems into a single inbox. The past year has seen co-founder and CEO Mathilde Collin finally turn that buzz into tangible growth. Her startup’s Series B round of $66 million (total funding now: almost $80 million) let Front make its first acquisition last October, a calendar-scheduling platform called Meetingbird. “We raised way more money than we needed,” Collin says. “We were actually not looking to acquire a company. But this company built on top of Front to make it available to our users.” Three months later, Front completely redesigned, repriced, and relaunched its app from scratch, leading to a boost in paying customers: 5,200 companies now, up from 4,500 at the beginning of the year. Front has also opened a new Paris office--a foreshadowing of Collin’s plans for international expansion, and a comfort zone for the native Parisian. --Cameron Albert-Deitch