Apple’s WebKit rules would cost iOS users nearly 30% of browser performance

Microsoft engineers have released benchmark results showing that a Chromium-based browser using its own rendering engine performs 28.6 percent higher than Safari in Apple’s Speedometer 3.1 performance test on iOS.

Kyle Pflug, group product manager for the Microsoft Edge web platform, released results Monday comparing a search prototype of Edge built with Apple’s BrowserEngineKit framework to Safari running iOS 26.5.1. The Blink-based prototype scored 49.27 versus Safari’s 38.3 on Speedometer 3.1, and also outperformed Safari by 13.1% on the JetStream 3 JavaScript benchmark (306.35 versus 270.9) and the MotionMark 1.3.1 graphics rendering benchmark by 2.1% (4,773.52 versus 4,673.68). Pflug described the work as a research prototype rather than a finished product, and the figures as preliminary results from his own device rather than laboratory conditions.

Apple requires all browsers on iOS to use WebKit, the engine that powers Safari, meaning that browsers like Chrome and Firefox on iPhone are effectively reskinned Safari instances. The EU’s Digital Markets Act theoretically changed this in March 2024, requiring Apple to allow alternative browser engines through BrowserEngineKit. Yet, more than two years later, no browser manufacturer has delivered an alternative engine to iOS. The companies cite technical hurdles and the requirement to release such a browser as an entirely separate app from their existing WebKit-based version.

Open Web Advocacy told The register the results illustrate a 17-year cost to consumers. The group called on the European Commission to open a specification procedure telling Apple precisely how to remove barriers to alternative engines, adding that restricting browser engines allows Apple to limit the capabilities of the mobile web and keep businesses dependent on native apps and App Store rules.