Google has been ordered to open up its app store to rivals following a major court case in the US.

Last year, a federal judge ruled the tech giant was running an illegal monopoly in how it controlled the distribution of apps on its Android operating system and via the Google Play Store.

Now, in the final ruling on the case, Judge James Donato has ordered Google to open up the Google Play store in the United States for three years, including allowing third-party app stores to be distributed from within Google Play, and giving third-party app stores access to the full catalogue of Google Play apps, unless developers choose to opt out individually.

Beginning in November, Google is also being forced to stop requiring its own payment system be used for apps on the Play Store, as well as allow developers to tell users about about other ways to pay from within the store, let developers link to other ways to download their apps outside of Google’s app store, and let developers set their own prices for apps.

In addition, the tech giant has been told that it can’t offer developers money or perks to launch their apps on the Play Store first or exclusively or to not launch on rival stores.

The company has been told it also cannot offer money or perks to device makers or mobile carriers to preinstall the Play Store.

The remedies are in response to the verdict delivered in the Epic Games v Google case in December last year, when a jury found that Google had monopoly power in the Android app distribution market and engaged in anticompetitive behaviour to maintain that monopoly.

The case had been brought by Epic, the maker of popular battle royale game Fortnite, over in-app purchases fees it said were unfair to third-party app developers.

Epic Games has recently filed a new lawsuit in the US against Google and Samsung, claiming that Google is now compelling Android customers – such as Samsung – to put barriers up between users and third-party app stores as a well of getting around the court ruling against Google.

Responding to the judge’s remedies in a post on X, Epic Games chief executive Tim Sweeney said: “The Google Play Store injunction lasts for three years.

“This means all app developers, store makers, carriers, and manufacturers have three years to build a vibrant and competitive Android ecosystem with such critical mass that Google can’t stop it.”

In a blog post, Google’s vice president for regulatory affairs, Lee-Anne Mulholland, said the technology giant would appeal the verdict and ask the courts to pause implementing the remedies.

“As we have already stated, these changes would put consumers’ privacy and security at risk, make it harder for developers to promote their apps, and reduce competition on devices,” she said.

“Ultimately, while these changes presumably satisfy Epic, they will cause a range of unintended consequences that will harm American consumers, developers and device makers.

“These Epic-requested changes stem from a decision that is completely contrary to another court’s rejection of similar claims Epic made against Apple – even though, unlike iOS, Android is an open platform that has always allowed for choice and flexibility like multiple app stores and sideloading.

“We are appealing that underlying decision and we will ask the courts to pause Epic’s requested changes, pending that appeal.”