Always-on monitoring of Interaction to Next Paint, the metric that replaced FID in March 2024. Sentry catches main-thread blocking, runaway third-party JS, and DOM bloat before users hit the 200ms p75 wall. Cortex handles the fix.
Continuous audits of mobile + desktop INP against Google's 200ms threshold and the documented diagnostics that explain why interactions are slow. Each rule maps to a primary web.dev INP doc. Sentry catches what fails. Cortex fixes it.
CrUX 28-day p75 INP on phone form factor under Google's 200ms 'Good' threshold. INP replaced FID as a Core Web Vital on March 12, 2024 and is the metric Google uses for the mobile interactivity signal.
CrUX 28-day p75 INP on desktop under Google's 200ms 'Good' threshold. Desktop interactivity matters for cart flows, dashboards, and any interaction-heavy page.
Lighthouse Total Blocking Time on mobile under 200ms. TBT is the lab proxy for INP - Lighthouse can't measure INP directly without real interactions, so TBT stands in.
Lighthouse mainthread-work-breakdown total under 3 seconds. Every millisecond of main-thread work past 50ms is a long task that delays the next interaction's paint.
Lighthouse bootup-time audit shows total JS execution under 2 seconds on the throttled mobile profile. Long bootup time is the single biggest INP contributor on JavaScript-heavy sites.
Third-party scripts (ad tags, analytics, chat widgets, A/B tools) consume less than 500ms of main-thread time. Third parties are the #2 INP contributor after first-party JS.
Total DOM tree under 1500 elements. Event-handler work scales linearly with DOM size - large DOMs make even simple interactions expensive.
Lighthouse unused-javascript audit shows less than 30% of total JS bytes go unused on page load. Unused JS is parse + compile + execute cost paid for nothing - and a known INP regression source.
Touch and wheel event listeners are registered as `passive: true`. Non-passive listeners block scroll-driven rendering and inflate INP for any scroll-triggered interaction.
Paste your homepage URL. Sentry runs PSI for mobile + desktop, pulls 28-day CrUX field INP, and inspects Lighthouse's main-thread, third-party, DOM-size, bootup-time, unused-JS, and event-listener diagnostics. No signup, instant results, always free.
Sentry fetches your site, runs every INP 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.
9 rules in the INP Sentry. Daily 3:30 AM ET sweep.
One brain. Thirty-six pairs of eyes. Sentries monitor every visibility signal that decides whether search engines, AI engines, and ad platforms show you. Cortex reads what they see, weighs it against a unified corpus of platform documentation, and acts. Every move follows a defined decision protocol: action stated, reason given, impact named.