Always-on monitoring of Time to Interactive. Google removed TTI from the Lighthouse Performance score in v10, but the underlying interactive audit still runs - and the metric remains the canonical answer to 'when does the page first respond reliably?' Sentry surfaces it for legacy dashboards. INP is the modern signal.
Continuous lab audits of TTI against Lighthouse's documented 3.8s 'Good' threshold and the four diagnostics that explain it. TTI is no longer in the Performance score - INP replaced it as the production interactivity signal - but the lab measurement is still useful for legacy comparisons. Sentry tracks both side by side.
Lighthouse interactive audit reports TTI under 3.8s on the throttled mobile profile. TTI marks the moment main-thread work, layout, and network all reach a quiet window long enough for the page to reliably respond to user input.
Lighthouse Total Blocking Time on mobile under 200ms. TBT is the modern signal Lighthouse uses for interactivity scoring since TTI was dropped in v10. Healthy TBT predicts a healthy TTI.
Lighthouse mainthread-work-breakdown total under 3 seconds. Main-thread work is the single largest TTI driver - every long task delays the interactive quiet window.
Lighthouse bootup-time audit shows total JS execution under 2 seconds on the throttled mobile profile. Bootup time is the single largest contributor to a late TTI on JavaScript-heavy SPAs.
Third-party scripts (ad tags, analytics, chat widgets, A/B tools) consume less than 500ms of main-thread time. Third-party long tasks keep pushing the TTI quiet window further out the more vendors a page loads.
Paste your homepage URL. Sentry runs PSI for mobile, pulls Lighthouse's interactive, total-blocking-time, mainthread-work-breakdown, bootup-time, and third-party-summary audits, and ships a per-rule report. No signup, instant results, always free.
Sentry fetches your site, runs every TTI rule, and renders the full result page before your next sip of coffee.
Each failed rule ships with a prescription paragraph. Hand it to engineering and the gap is closed before lunch.
Add your site to the daily Sentry sweep with one click. New regressions get caught the next morning.
5 rules in the TTI Sentry. Daily 3:30 AM ET sweep.
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