With the fanfare of free gift cards and helium balloons, Froyo World celebrated its five-year anniversary on Sunday — a feat in the hypercompetitive world of New Haven frozen yogurt.

In 2010, owner William Bok teamed up with landlord Yale University Properties to open Froyo World, becoming Connecticut’s first self-serve frozen yogurt establishment. The success of the High Street location has inspired dozens of franchise locations in New England and abroad, Bok said. Of the franchises he oversees, he added, he has found greatest success in the original New Haven location. Still, Froyo World has had its share of challenges, specifically when competition opened nearby.

“When we opened we had crazy business,” Bok said. “After everybody saw our success, people started opening around us. So, being successful brought more competition.”

Since Froyo World opened, three frozen yogurt establishments opened and subsequently closed within three blocks of Froyo World. Flavors opened in 2011 on York Street, while Polar Delight and Pinkberry both opened in 2013 on Chapel Street. Flavors shut its doors earlier this month; Polar Delight and Pinkberry both closed last year, leaving Froyo World and Go Greenly, at 48 Whitney Ave., as the two frozen yogurt shops near campus.

Bok said he partially attributes the High Street location’s success to University Properties. Froyo World is part of UP’s umbrella group of businesses, The Shops at Yale, which the property management office includes in its promotional materials and advertising efforts.

Zarko Stojanovski, a manager at Tropical Cafe Smoothie, a newly opened store renting from UP, said he had similar experiences with landlord assistance. UP has provided valuable marketing tools, such as lamppost signs on Broadway, Stojanovski said.

“Many people from Yale University Properties have approached us and asked how they can help us succeed,” Stojanovski said.

UP does not own any of the properties that housed the three frozen yogurt shops that closed down.

Bok also attributed his success to the loyalty and diversity of clients. Roughly one-third of patrons are Yale students, Bok said. But the majority of patrons are able to visit the store year-round. These visitors include professionals who work in offices nearby, local residents and families on downtown excursions.

Students interviewed said there was a surfeit of frozen yogurt stores in downtown New Haven.

Eliza Scruton ’17 said Pinkberry’s decision to open around the block from an existing frozen yogurt shop seemed like an odd choice.

Nicole Clark ’16 said she believed the surplus of frozen yogurt shops resulted from different landlords wanting to tap into the frozen yogurt market. Kenneth Jackson ’17 said he believes frozen yogurt has also become less popular over the last year or two, intensifying the competition among the frozen yogurt stores.

“It was a bit of a fad I think, and so maybe now the popularity is dipping,” Jackson said. “I think I go [to frozen yogurt stores] about the same amount, but they seem emptier.”

Since Froyo World opened in 2010, 28 franchise locations have opened throughout Connecticut, Massachusetts, Rhode Island and New Jersey, and an additional eight have opened abroad in Puerto Rico and Australia. Although the different franchise locations have modified the store’s interior designs with new lighting and granite countertops, Bok said he chose to keep the New Haven store’s interior the same as when the shop opened.

“We upgraded, upgraded and upgraded. But, we kept New Haven the same because we wanted it to be the original,” Bok said.

Connecticut is home to 18 Froyo World locations.