The joyous cries of dozens of children sounded from the Volo sports complex in Brewers Hill on Sunday afternoon.

Their parents watched, food and drink in hand, as they lined up for a turn in the red-and-yellow bouncy castle, got their faces painted and flitted between four sandy beach volleyball courts and a grassy field.

Adults and kids bopped to pop songs in front of a DJ booth before grabbing plates of free birthday cake. After all, they had all gathered there to celebrate the Volo Kids Foundation’s 10th birthday party.

“There’s just a lot of joy here,” Jen Rifkin, the foundation’s executive director, said at Sunday’s event. “Everybody’s connecting, and that’s just what it was always supposed to be about: bringing communities together.”

Baltimore-based Volo marked multiple milestones this year.

In the 15 years since its founding, Volo Sports has grown to be the largest provider of social sports in the nation. And the company’s nonprofit arm, launched in 2015, has grown too. What began with fewer than 100 young participants playing flag football at a Baltimore rec center has become a multicity program serving thousands of children with free sports programming.

Sports have always been a part of Giovanni “Gio” Marcantoni’s life. He played baseball and basketball growing up, and football at Calvert Hall College High School.

But it was bocce, an 18th-century Italian game, that would launch Marcantoni’s entrepreneurial journey in creating the company.

In his mid-20s, Marcantoni worked in the finance industry and was looking for a hobby and a place to connect with other young people in Baltimore.

He played in a few sports leagues but noticed other participants quitting in the first or second week because of how intense and competitive games could feel, he said.

“Maybe there’s something else we could do and kind of look at this differently,” Marcantoni, Volo Sports’ CEO and founder, thought.

And so in 2010 the Baltimore Bocce League — Volo Sports’ precursor — was born.

“We played on grass, not even on real bocce courts,” he said. “The whole thing was, you show up, you don’t need to know anybody. You can sign up online, and we’re gonna teach you how to play bocce.”

It wasn’t competitive bocce — just casual and sometimes silly.

Over time, the league grew. It started playing in Hampden and Canton, moving from one day a week to two or three times a week

By 2013, Marcantoni had bocce and Skee-Ball leagues in Baltimore, New York and Denver.

It became a part-time job for Marcantoni. And, when his career wasn’t going in the direction he wanted, he jumped into it full time.

“People are craving something to do, to meet people, to have community,” Marcantoni said. “Clearly, the market wants it. The consumer wants this.”

Volo acquired New York-based ZogSports, the second-largest social sports platform with over 120,000 players, in June. ZogSports operated leagues in New York, New Jersey, D.C., Los Angeles, San Francisco and San Jose, California.

The acquisition will increase Volo Sports’ total registrations this year to nearly 900,000, Marcantoni said.

Five years after Marcantoni started the Baltimore Bocce League, unrest sparked in the city.

Freddie Gray, a young man from Baltimore’s Sandtown-Winchester neighborhood, died of a spinal cord injury he sustained in police custody. The protests and outrage following his death shook the city.

Marcantoni found himself in town hall after town hall, listening to entrepreneurs, city officials and other stakeholders debate how they could join forces to unite communities and improve Baltimoreans’ lives.

Out of those meetings came the idea for new programming, aimed at children instead of adults. The company was already a sports operator, Marcantoni reasoned, with all of the equipment and space necessary. How hard could it be?

“It was harder than we thought,” Marcantoni said. “There’s some extra red tape.”

Before he was Mayor Brandon Scott, the then-councilman representing the second district offered Marcantoni his help. He’d find a space at Herring Run Recreation Center for Marcantoni’s new kids program, he said — but only if it were free.

“[Marcantoni’s] face turned really red, really quickly,” Scott said at the Sunday event. “and I said, just tell me how much it costs. Don’t worry about it. We’ll figure out ways to raise the money.”

The two teamed up, and Scott started coaching kids alongside Marcantoni as the program expanded to other places in the city.

Scott, who has participated in Volo’s adult leagues, still coaches for the foundation at Herring Run.

In the 10 years since its founding, the Volo Kids Foundation has served more than 80,000 children across the nation, Rifkin said, offering programming in 10 cities.

This year, Marcantoni expects the foundation to provide programming for roughly 30,000, he said.

Every registration, game and postgame snack remains free.

Devin Robertson, an attendee of Sunday’s festivities, began registering his 8-year-old daughter, Zoey, in Volo Kids programs three or four years ago, after DJ’ing for some of Volo’s adult events.

He said he appreciates that the foundation offers his daughter a chance to try different sports without being cost-prohibitive.

“With this I say give it a shot, and if she doesn’t like it, it doesn’t cost us anything,” he said.

She’s tried a little bit of everything: soccer, flag football, kickball, dance and volleyball.

Her favorites? Kickball and dance.

“I like the whole atmosphere,” Robertson, a 41-year-old Baltimore resident, said. “I think it’s a great thing.”

At Sunday’s event, Marcantoni presented the Volo Kids Foundation with a $100,000 donation from the sports company to its nonprofit partner.

“We made something that was sustainable, that didn’t just give kids something for a little bit then took it away because we couldn’t get funding,” Marcantoni said. “It’s a proud moment.”