Apple Declares Interop 2025 a Landmark Year for Cross-Browser Compatibility
In a recent update on its WebKit blog, Apple has hailed Interop 2025 as a pivotal year for enhancing cross-browser interoperability. This collaborative initiative, involving major tech entities like Apple, Bocoup, Google, Igalia, Microsoft, and Mozilla, aims to streamline web development by ensuring consistent behavior across different browsers.
The Interop Project: A Unified Effort
Launched to address common challenges in web development, the Interop project focuses on enabling developers to write code that functions seamlessly across various browsers. By the end of 2025, the project had identified 19 key focus areas and five investigative domains spanning CSS, JavaScript, Web APIs, performance, and platform health. Remarkably, the pass rate for selected tests across all browsers surged from 29% at the year’s start to an impressive 97% by year-end. Experimental versions of Chrome, Edge, Firefox, and Safari achieved a 99% pass rate, underscoring the project’s success.
Apple’s Perspective on Interop 2025
Apple emphasized the collaborative nature of the project, stating, Each year, the Interop project chooses its focus areas through a collaborative process with proposals, research into what web developers need, and debates about priorities. The company highlighted Safari’s significant progress, noting it made the largest leap among browsers, climbing from a 43% to a 99% pass rate. This advancement was particularly noteworthy given the substantial engineering efforts required within WebKit.
Key Focus Areas and Achievements
Several critical areas were addressed during Interop 2025:
– Anchor Positioning: This feature allows developers to position popovers, menus, and tooltips relative to any element using only CSS, eliminating the need for JavaScript-based positioning libraries.
– Same-Document View Transitions: Enabling smooth UI animations between states directly in the browser, this feature was supported in Safari versions 18.0 and 18.2. Its broader interoperability means developers can now implement it without resorting to browser-specific fallbacks.
– Navigation API: Replacing older history-based methods, the Navigation API offers modern navigation handling for single-page applications. Apple introduced support in Safari 26.2, emphasizing that early interoperability reduces long-term compatibility issues.
Comprehensive Progress Across the Platform
Beyond these highlights, Apple detailed contributions across all 19 focus areas, including:
– CSS and UI Features: Enhancements such as @scope, backdrop-filter, text-decoration, layout systems, and writing modes.
– API Developments: Advancements in Storage Access API, URLPattern, WebRTC, WebAssembly, and the scrollend event.
– Investigative Areas: Efforts in accessibility testing, mobile testing, and Gamepad API testing laid the groundwork for future improvements.
Apple concluded by highlighting the collective investment from all browser engines, noting that their scores converged at the top by year’s end. This shared progress ensures the web remains predictable, stable, and developer-friendly across platforms.
