Thousands braved the heat Saturday to see their favorite performers including headliners Demi Lovato, Zedd and Big Sean at the Billboard Hot 100 Music Festival at Northwell Health at Jones Beach Theater.

The daylong event — which began at 12:30 p.m. and ended at 11 p.m. — was at capacity by midafternoon and gave nearly 15,000 concertgoers access to some of the biggest names in the industry, while also introducing audiences to lesser-known acts.

“The festival is focused more on pop and really, really recent acts,” said John Amato, president of The Hollywood Reporter-Billboard Media Group that organized the event with LiveNation.

Performers were spread across four stages with newer artists such as electronic up-and-comer Ben Alessi, indie pop band Great Good Fine OK and rapper Ty Dolla $ign performing on the Heatseekers or Beach sets and bigger names saved for the Sun and Hot 100 stages.

Bea Miller, rappers Gucci Mane and Big Sean, Lovato and electronic dance music sensation Zedd all performed separate sets on the main Hot 100 stage.

The demographic of this festival, which on Saturday was expected to sell out for the third consecutive time it was held on Long Island, tends to skew younger, attracting many teenagers and 20-somethings.

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“I think that when we started this, we specifically built it to be that festival for millennials and younger millennials specifically,” Amato said.

One of the goals of this event is to introduce audiences to artists with promise while simultaneously providing access to chart-topping performers from various genres.

“I think the lineup is consistent and we’re delivering the same product year in and year out, which is pop, hip-hop and EDM [electronic dance music] and I think that Long Island specifically gravitates towards that,” Amato said.

For the first year the festival was held on Long Island two years ago, the capacity was 25,000. In 2016 and 2017, attendance was capped at 15,000 to “improve the customer experience,” Amato said.

“I think it’s really fun to be at a festival because there are fans of everybody’s music here who maybe have never heard of you and may stop by your stage and catch your performance,” said singer Phoebe Ryan, who made her inaugural appearance on the Sun Stage on Saturday. “It’s a really good opportunity to meet new people and to share. It’s really great.”

Sophia Mangone and Besarta Sinanaj, both 14 and of Ardsley in Westchester County, attended the concert Saturday for a second consecutive year.

“I like this festival set up more because there are so many more options than a regular concert,” Sophia Mangone said.

The friends arrived with VIP tickets about 3 p.m. hopeful that Lovato, whom they were most eager to see take the Hot 100 Stage at 7:40 p.m., would perform her summer release “Sorry Not Sorry.”

During her 25-minute set, Lovato delivered.

Zedd and Big Sean closed out the festival’s Hot 100 stage with separate one-hour sets.