Why Lighthouse Audits Mobile & Desktop Separately

Why Lighthouse Runs Them Separately

Tools like Google Lighthouse (and analyzers built upon it) audit mobile and desktop versions independently because the context is so different.

• Simulated Environment: The mobile audit typically simulates a slower network connection (like 4G) and a less powerful device (like a mid-tier smartphone) to reflect real-world mobile usage conditions.
• Different Metrics Thresholds: Performance expectations and scoring thresholds (e.g., for Core Web Vitals) can sometimes differ slightly between mobile and desktop due to these environmental factors.
• User Agent: The audit uses a mobile user agent string, which might cause your server to deliver a different, mobile-optimized version of your site if configured to do so.

Auditing both versions ensures you identify performance bottlenecks and usability issues specific to each platform, allowing you to provide a consistently excellent experience for all users, regardless of how they access your site.