Digital Experience Monitoring
What the domain tests
Digital Experience Monitoring tests real user and synthetic visibility: browser agent deployment, Core Web Vitals, JavaScript errors, session replay, synthetic monitor types, locations, and alerting. The exam asks you to separate a real user regression from a monitor artifact.
Core rules
- Browser agents come in Pro, Lite, SPA, and copy/paste variants. SPA agents handle route changes without full page loads; Lite reduces overhead at the cost of some detail.
- Key events include PageView, BrowserInteraction, AjaxRequest, JavaScriptError, PageAction, and SessionReplay. Segment PageView by device type, geography, and route before concluding.
- Core Web Vitals: LCP measures loading, INP measures responsiveness (it replaced FID), and CLS measures visual stability. Alert on p75, not averages.
- Synthetic monitors: ping, simple browser, scripted browser, and API test. They run from public or private locations; scripted browser uses Selenium/WebDriver and secure credentials.
- Session replay reconstructs DOM changes; configure masking and blocking for sensitive fields.
- Synthetic checks validate availability and scripted flows; they do not replace real-user measurement.
Worked example
Mobile LCP p75 worsens in one region, but a simple browser monitor passes. Simple browser runs from a fixed location and may not emulate a mobile network. Query PageView with deviceType = 'Mobile' and the region, compare LCP p75 by route, then inspect third-party scripts. If needed, add a scripted browser monitor with network throttling.
Traps
Alerting on averages; assuming every session is captured; forgetting SPA route instrumentation; using a single synthetic location as proof of global health; brittle selectors; ignoring privacy settings.