A judge in California issued a permanent injunction that stops Apple from preventing app developers from directing users to payment methods outside the App Store - a decision that was seen by many as a loss for Apple.
However, the court also ruled against Epic on nine out of 10 issues and ordered it to pay millions of dollars in costs but Epic chief Tim Sweeney.
The 'Fortnite' developers had argued that Apple's strict rules surrounding the iOS platform amounted to a monopoly but the court found that Epic had failed to prove its case.
Judge Yvonne Gonzalez-Rogers said: "The court cannot ultimately conclude that Apple is a monopolist."
Apple had described the ruling as a clear victory and argue that the issue can be resolved with communication between app developers and users.
But the injunction allows developers to link to their own purchasing mechanisms and may mean Apple miss out on the 30 per cent cut taken from their payment system.
The court has given Apple a 90 day grace period before the injunction takes effect and the tech giant could yet appeal the ruling.
Sweeney had tweeted after the verdict: "Today: Lost a court case, climbed a mountain, read hundreds of pages of legal papers, wrote some code. Just as determined as ever to fight on until there is genuine developer and consumer freedom in software, and fair competition in each mobile platform software component."