Responsive design — meaning a site that automatically adjusts its layout for different screen sizes — is no longer a feature. It’s a baseline requirement. Every site built in the past decade should be fully responsive. The question to ask in 2025 is not “is it responsive?” but rather: how does it perform on mobile?

Specifically, ask about:

• Page load speed on mobile — slow mobile sites lose visitors and rank lower in Google search results
• Core Web Vitals — Google’s set of performance metrics that directly affect your search ranking
• Mobile vs. desktop optimization — a lean, fast mobile experience sometimes requires different design decisions than the desktop version
• Touch-friendly navigation — buttons, menus, and forms should be easy to use on a phone screen without pinching or zooming

A beautiful site that loads slowly on a phone is a liability, not an asset.