Apple's WebKit Rules Reportedly Cost iOS Users Almost 30% Browser Performance

Microsoft engineers have published benchmark results showing that a Chromium-based browser using its own rendering engine scores 28.6% higher than Safari on Apple's own Speedometer 3.1 performance test on iOS.

Kyle Pflug, group product manager for the Microsoft Edge Web Platform, published results on Monday comparing a research prototype of Edge built with Apple's BrowserEngineKit framework against 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 on the JetStream 3 JavaScript benchmark by 13.1% (306.35 vs. 270.9) and on the MotionMark 1.3.1 graphics rendering benchmark by 2.1% (4,773.52 vs. 4,673.68). Pflug described the work as a research prototype rather than a finished product, and the numbers as preliminary results from his own device rather than lab conditions.

Apple requires all browsers on iOS to use WebKit, the engine that powers Safari, meaning browsers like Chrome and Firefox on iPhone are effectively reskinned Safari instances. The EU's Digital Markets Act theoretically changed that in March 2024, requiring Apple to allow alternative browser engines through BrowserEngineKit, yet more than two years later no browser maker has shipped an alternative engine on iOS. Companies cite technical barriers and the requirement to publish any such 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 proceeding instructing Apple precisely how it must remove barriers to alternative engines, adding that restricting browser engines allows Apple to limit what the mobile web is capable of and keep businesses dependent on native apps and App Store rules.