Monitoring: PageSpeed and RUM

PageSpeed scans, first-party Web Vitals, read-only suggestions, and field-data interpretation.

2 min readPart of Performance Optimisation

Monitoring helps answer whether a performance change helped real visitors. Performance Optimisation combines explicit PageSpeed scans, first-party Web Vitals, local telemetry, and read-only suggestions. Monitoring never silently applies a code or settings change.

PageSpeed scans

An administrator must provide a PageSpeed API key and choose a public URL and mobile/desktop strategy. The scan is queued as background work, cached for reuse, and may be scheduled through auto_rescan. The request sends the selected public URL and strategy to Google; it does not send WordPress cookies or administrator credentials.

wp wppo pagespeed scan --url=https://example.com --strategy=mobile
wp wppo pagespeed results --url=https://example.com --strategy=mobile

Real-user monitoring

With RUM enabled, the browser posts bounded LCP, INP, and CLS samples to the site\’s public beacon. The endpoint uses a rolling token, rate limits, clamped values, a rolling retention window, and local aggregation. It does not store names, emails, form values, user IDs, or cookies with samples. Disabling RUM stops collection; uninstalling removes the plugin\’s stored RUM data.

Suggestions and anomaly notices

The suggestion engine combines telemetry, PageSpeed, and RUM evidence into a prioritized next step. The Dashboard\’s Guided Next Step shows one server-selected action and a server-type note; the full list remains available below it. Adaptive tuning and AI-client use are disabled by default and retain minimum-sample/cooldown gates.

Reading field data

Core Web Vitals are evaluated at the 75th percentile of real visits, not only at the median. Compare the same page, device class, and time window before and after a change. A lab score can improve while field LCP or INP worsens for a particular template or audience.

Settings

Key	Default	Purpose
`pagespeed_api_key`	`\'\'`	PageSpeed authentication; keep it out of exports and logs.
`high_value_urls`	`[]`	URLs for scheduled rescans.
`auto_rescan`	`\'\'`	Off, daily, or weekly.
`rum_enabled`	`false`	Enable the first-party field beacon.
`rum_sample_rate`	`100`	Client sampling percentage, subject to beacon limits.
`server_timing_enabled`	`false`	Expose request-stage timing headers.

Verify

Run a scan explicitly, inspect the result and trend card, then load a frontend page with the network panel open. If RUM is missing, check the setting, browser blockers, token rotation, and rate limits. Never paste a PageSpeed key or beacon token into a report.