By Sarah E. Needleman

A California federal judge granted the maker of "Fortnite" a partial reprieve in its battle against Apple Inc., saying Epic Games Inc. can maintain access to the tech giant's software-development tools but that its blockbuster videogame, for now, would remain out of the App Store.

U.S. District Judge Yvonne Gonzalez Rogers issued the decision late Monday after a virtual court hearing in which attorneys for Epic and Apple defended their companies' positions. "Apple has chosen to act severely, and by doing so, has impacted non-parties, and a third-party developer ecosystem," Judge Gonzalez Rogers wrote in her ruling.

Apple said it would revoke Epic's access to tools needed to distribute and update software across its devices on Aug. 28 unless Epic removed the mobile-payment system it introduced in "Fortnite," which skirted Apple's 30% commission on in-app purchases.

Though "Fortnite" is free to play on videogame consoles, computers and mobile devices, Epic allows players to buy virtual perks and access to special game modes. The shooter-survival game has more than 350 million players world-wide, according to Epic.

Epic said Apple's decision would imperil its business, including its flagship product, Unreal Engine, a software tool kit used by millions of developers world-wide for making games, television and movie special effects and other types of digital content.

The next hearing in the case is scheduled for Sept. 28. In its complaint, Epic asked the court to stop Apple from engaging in anticompetitive conduct with its App Store practices and take steps to restore competition.

Apple has said that the unapproved modification to "Fortnite" violated its guidelines and described Epic as willfully breaching a contract and thus responsible for its customers' plight. The company has also defended its role as a gatekeeper in protecting users' privacy and security as well as collecting fees to support those efforts.

"What Epic has done is to break that model and profit by it and placed the customers in the middle," Apple attorney Richard Doren said during Monday's virtual court appearance.

Epic sued Apple as well as Alphabet Inc.'s Google on Aug. 13 in federal court after the companies pulled "Fortnite" from their respective app marketplaces. "It was the only way to try and break the chokehold that Apple has on its payment system, and it's a prohibition on any kind of competition," said Epic attorney Katherine Forrest during the hearing.

The legal battle could have wide implications in the global market for mobile apps, which last year reached $120 billion in consumer spending, according to App Annie Inc., as it could upend how app stores and developers divvy up sales for paid downloads and virtual goods -- or how apps accept payments all together.

Companies including Microsoft Corp., Facebook Inc. and Spotify Technology SA as well as small, independent game studios have criticized Apple and Google for the power they wield in app stores.

Judge Gonzalez Rogers is hearing the case between Epic and Apple as well as a 2019 case brought by app developers who claimed the tech giant's App Store operations violated federal antitrust law. The developers' lawsuit came a month after the Supreme Court, in a 5-4 opinion, determined individual consumers could sue Apple for being forced to buy apps exclusively from the iPhone maker.

Epic has been an outspoken critic of Apple and Google's app-store practices for years, saying the companies' 30% commission on in-app purchases and download fees is excessive and that developers shouldn't be restricted to using only their payment systems to process sales. Epic itself charges a 12% commission in its PC game marketplace.

Write to Sarah E. Needleman at sarah.needleman@wsj.com