Apple on Friday appealed a federal judge's verdict in its legal battle with Fortnite-maker Epic Games over control of the App Store.
Apple is asking the Ninth Circuit Court of Appeals in San Francisco to overturn the 185-page ruling by US District Court Judge Yvonne Gonzalez-Rogers.
The judge ordered Apple to loosen control of its App Store payment options, but said Epic failed to prove any antitrust violations.
Epic last month filed its own appeal.
"We will fight on", Epic chief executive Tim Sweeney tweeted when the company confirmed its plan to contest the verdict.
Apple said in the days after the ruling by Gonzalez-Rogers that it was "very happy" with the decision but had left open the door to appeal.
The companies had opted for a so-called bench trial in which a judge rather that a jury hears the evidence and decides on a verdict.
Epic launched the case aiming to break Apple's grip on the App Store, accusing the iPhone maker of acting like a monopoly in its shop for digital goods or services.
"For me, it is a win for Apple in that the judge clearly said they are not engaging in monopolistic behavior," Creative Strategies analyst Carolina Milanesi said after the verdict.
"I don't think it is a problem for Apple from a revenue perspective."
The judge barred Apple from prohibiting developers from including in their apps "external links or other calls to action that direct customers to purchasing mechanisms."
Apple can still mandate that its payment systems is used for in-app transactions.