Categorizing device types by desktop, mobile and tablet no longer works in 2021. It is oversimplified, meaningless and likely breaks your current performance analysis on a modern responsive website. As #perfmatters we need meaningful monitoring that takes into account the modern web: - Screen dimensions - Device pixel ratios - Image and CSS breakpoints - Connections Keeping it both simple and meaningful is however not easy! Learn about the different approaches and how to apply this to your existing RUM monitoring solutions: be it free (Google Analytics), open source (Boomerang) or commercial.