Google has lost its appeal against a major antitrust ruling in the US, with a federal court upholding a decision that forces the tech giant to open up its Google Play Store to rival app stores and third-party billing systems.

The case, brought by Fortnite developer Epic Games, could have sweeping implications for Android app distribution worldwide.

The unanimous verdict confirms that Google violated antitrust laws by restricting competition on Android devices.

The original ruling, issued in late 2023, had been on hold pending this appeal.

That hold is now lifted, meaning Google will soon be required to implement sweeping changes to its Play Store practices.

Epic CEO Tim Sweeney called the outcome a “total victory,” confirming that the Epic Games Store will launch on Android via Google Play.

The ruling compels Google to allow third-party stores within its ecosystem and bans practices such as forcing developers to use Google’s in-app payment system.

“This is a win for developers and consumers alike,” said Sweeney on X. “Android users will now get real choice.”

Google, of course, strongly criticised the decision.

Lee-Anne Mulholland, Google’s VP of regulatory affairs, claimed the changes “will significantly harm user safety” and “undermine innovation.”

Analysts suggest the long-term financial impact on Google could be substantial.

Bloomberg estimates suggest that third-party billing and app store competition could cut into Google’s app store revenue by as much as $1.5 billion ($A 2.25 billion) annually.

Epic’s win also signals trouble for Apple, which is facing a separate but similar legal battle with the game publisher.

However, unlike in its case against Google, Epic largely lost its antitrust claims against Apple in 2021.

Epic has also settled its separate antitrust case against Samsung, dropping claims that the company colluded with Google to stifle competition through Android’s default settings.

For now, Google is expected to appeal again, possibly all the way to the US Supreme Court.

In the meantime though, the Android ecosystem is set to shift dramatically.