The startup's technology for tournament-style play in which victors get cash prizes debuted Wednesday in more than 150 games available at Apple's online App Store.
It has been available for games tailored for Android-powered smartphones or tablets for about a year.
"Skill gaming has happened in the off-line world for hundreds of years; down to the dollar-a-hole game friends play on the golf course," Skillz co-founder and chief operating officer Casey Chafkin told AFP.
"This is just taking it to the online world."
Cash prizes for tournament matches, even if only pitting two players against one another, sidestep gambling laws that ban pay-outs for games of chance.
Chafkin contended that winning money for besting a friend at Zynga's "Words With Friends" game would be on par with a marathon runner being handed a check for being first across the finish line.
Skillz announced that more than 300 studios representing thousands of mobile games have signed onto the startup's platform.
Launch titles include "Strike!" bowling and "Survival Run with Bear Grylls."
Skillz provides software to build its capability into titles, then collects entry fees for tournaments; pays out shares to winners, and splits proceeds with game makers.
"The fundamental problem we are trying to solve here is that there aren't a lot of monetization options that work well for developers," Chafkin said.
Digital ads popping up in games typically distract or annoy players, and selling virtual goods tends to be effective only in titles such as "Farmville" or "Clash of Clans" where people are building fantasy worlds, he maintained.
The number of registered accounts at Skillz has grown to 1.5 million since the kit for Android mobile game makers was released a year ago.
The Skillz software kit for Apple gadgets was in a private test mode for four months before its release on Wednesday.
"It is about fostering competition, and for those interest in something more than points or bragging rights," Chafkin said.
"The way we think about this, we are enabling e-sports for everyone."
Video games have become tournament level, spectator competitions in a booming trend referred to as "e-sports."
Skillz helped pioneer the skill-based gaming trend, and scores of competitors have dived into what is projected by analysts to quickly balloon into a multibillion dollar industry.
For details of the latest launches and news from Samsung, Xiaomi, Realme, OnePlus, Oppo and other companies at the Mobile World Congress in Barcelona, visit our MWC 2025 hub.