In March, Roblox debuted on Wall Street. As of Friday, it was worth $44 billion and more than 43 million players used it each day — more than double the number of daily users it had two years ago. One of the most striking differences, though, was the age of the crowd of hundreds of game developers to whom Mr. Baszucki was speaking in Fort Mason, a former military base along San Francisco’s waterfront.

Not long ago, the crowd might have been made up mostly of children. On Thursday, many were young adults. And as they have grown up, Roblox, a colorful, blocky platform that offers millions of online games of all types, from exploring tropical islands to fostering digital pets, has attempted to grow up with them.

Roblox’s effort to keep in touch with an older audience while maintaining a safe environment for its youngest users offers both a road map and a cautionary note for other internet companies attempting the opposite: engaging with a younger audience.

While Roblox has often been lauded for its efforts, protecting its young users has been a constantly evolving battle. The company reviews game content, offers parental controls and has chat filters that block profanity and information that can be used to identify people. Even so, explicit material slips through the cracks. There have been games that depict users’ avatars engaging in graphic sexual activity and recreations of mass shootings.

Like many other internet platforms, moderation has been a “really tricky problem for Roblox to get their arms around,” said Jeff Haynes, the senior editor of web and video games at Common Sense, a children’s advocacy and media ratings group.

Roblox’s shift toward a mixed-age audience comes as the privacy and vulnerability of children online is gaining global attention. Earlier this month, a Senate subcommittee hearing spent several hours listening to a whistle-blower detail concerns that Instagram is harming its teenage users. The whistle-blower, a former employee of Instagram’s owner, Facebook, is also expected to testify in the coming weeks before government officials in Britain and in the European Union.

Mixing older users with Roblox’s traditional crowd poses other safety risks, such as the possibility that young children are exposed to predators or recruited by extremist groups. The company has tried to crack down on such misconduct, and Mr. Baszucki said he recognized that integrating various ages on his platform was “a challenge.” But he said building an online world that was safe and open to all was part of his vision for the so-called metaverse, an idea that people can share a massive online universe together.

“We’re optimistic we can build this society that really is accessible to all ages,” Mr. Baszucki said in an interview after his speech.

Roblox was started in 2004 with the premise that most of its users were underage, so it put safeguards in place to protect children from online harassment and predators. It has long been wildly popular with children, particularly those between 9 and 12 years old.

Mr. Baszucki, who has a background in educational software, envisioned Roblox as a place where children could learn to code, explore virtual worlds, play and socialize, especially if their real-life school experience was unfulfilling. (Roblox’s chief product officer, Manuel Bronstein, recently joined The New York Times Company’s board of directors.)

The company makes money selling a digital currency called Robux, used to purchase in-game items, and it splits its profits with the independent developers that create the universe’s many games. Developers are tied to Roblox more closely than the content creators of social media platforms like Twitter, TikTok, Snapchat and Instagram, where teens say they are often confronted by toxic material.

“We’re less sharing our life, and we’re more, ‘Let’s play hide-and-go-seek, or let’s go to ancient Rome,’” Mr. Baszucki said.

This month, Roblox said that, for the first time, more than half of its users were older than 13. It recently announced new tools designed to attract older players to the platform, like more-lifelike avatars; the ability for developers to restrict some games to 13-and-older players, or possibly 17-and-older; and a voice chatting feature available to those who are at least 13. To verify their age, users can upload government-issued identification along with a selfie.

Earlier this month, Roblox updated its community standards to ban any depictions of romance or discussion of political parties. It also explicitly barred terrorist or extremist groups from recruiting or fund-raising on the site — an issue that has plagued social media companies like Twitter for years.

Mr. Baszucki said integrating older users while maintaining the standards of civility and good behavior that the platform is predicated on is a “huge responsibility.” But he was optimistic that the company would be successful, he said, because Roblox had a history of children behaving better than the adults on other social platforms.

Child safety experts said that as other sites try to broaden their appeal to children — Facebook, for instance, said it would create an Instagram product tailored specifically for those 13 and younger, before postponing those plans — they could learn important lessons from Roblox.

Titania Jordan, the chief parent officer at Bark, a tech company that uses artificial intelligence to monitor children’s devices, said that although bad behavior can sometimes slip through the cracks at Roblox, the company is still “commendable” in its approach to child safety, especially compared with sites like Facebook, Instagram and TikTok.

One Roblox tool other companies could implement, she said, was the ability to turn on parental controls that children cannot disable. Ms. Jordan said she would feel much better about letting her 12-year-old son use Snapchat if she could, for instance, enter a pin code at a certain time and lock the app for the rest of the night. Having an age verification system backed by an I.D. was also comforting, she said, compared with apps where it is easy to enter any age and create an account.

The fact that Roblox has devoted a good part of its design to combating misconduct and illicit material but still faces criticism could be another lesson to companies like Facebook, said Mr. Haynes, of Common Sense. He said it could make social platforms — many of which already devote considerable resources to policing for offensive or violent content — try even harder before believing they can safely offer something for a younger audience.

Roblox’s young developers are also optimistic. After all, they know what’s on the internet outside the confines of Roblox’s digital world.

“You can always find small examples of something slipping through — someone spelling a curse word in a weird way, everyone’s seen that. But compare that to the open internet,” C.J. Oyer, a 23-year-old developer who grew up playing Roblox, said at the company conference.