Real User Monitoring (RUM) captures performance and experience data from real users during their actual visit. It provides so-called field data from real-world usage.Open glossary entry → measures how a website actually performs for real visitors. Data about load times, Interaction to Next Paint (INP) measures how quickly a page responds to user input across all interactions and represents interactivity.Open glossary entry → and stability is collected and evaluated in users' browsers, across different devices, networks and locations.

This so-called Field data are performance measurements based on real users and their actual devices and connections. They show whether a performance problem is genuinely relevant.Open glossary entry → differs from Lab data are produced in a simulated test environment with fixed device and network conditions. They help identify the technical causes of performance problems.Open glossary entry →:

  • Field data (RUM) comes from real usage and reflects varied real-world conditions.
  • Lab data is produced under standardised test conditions, for example in performance tools.

For Search Engine Optimization (SEO) covers all measures that help a website become more visible in unpaid (organic) search results.Open glossary entry →, field data is particularly relevant because Google draws on real-world measurements, among other things, to assess user experience. RUM helps identify problems that lab tests alone do not reveal, such as slow load times on certain devices or connections. This makes it easier to prioritise performance measures.