Always-on monitoring of First Contentful Paint - the earliest moment a real user sees text or images on the page. Sentry catches render-blocking resources, missing compression, font-loading stalls, and third-party origin explosions before they cascade into LCP failures. Cortex handles the fix.
Continuous audits of mobile + desktop FCP against Google's 1.8s threshold and the documented diagnostics that explain why the first paint stalls. FCP is LCP's predecessor - what fails here fails LCP next. Sentry catches it. Cortex fixes it.
CrUX 28-day p75 FCP on phone form factor under Google's 1.8s 'Good' threshold. Field FCP is what real users on real networks experience.
CrUX 28-day p75 FCP on desktop under Google's 1.8s 'Good' threshold. Desktop FCP often falls under 1s for well-optimized sites.
Lighthouse mobile-emulated FCP under 1.8s. Lab FCP is deterministic and surfaces regressions before CrUX field data updates.
Server response time under 800ms. FCP = TTFB + render-blocking critical path + paint - if TTFB alone consumes the FCP budget, no front-end optimization can recover it.
Zero synchronous `<script>` or unscoped `<link rel='stylesheet'>` in the head blocking the FCP critical path. Render-blocking is the largest controllable FCP variable on most sites.
HTML, CSS, and JS are served with gzip or Brotli encoding. Brotli + smaller payloads = earlier FCP since the browser receives critical-path resources sooner.
Every @font-face declares font-display: swap, fallback, or optional. Default font-display (block) hides text up to 3 seconds while the font downloads - effectively delaying FCP for any text-heavy page.
`<link rel='preconnect'>` declarations for the cross-origin hosts that serve render-blocking resources. Skips the DNS + TCP + TLS round-trips that bloat FCP on cold connections.
Lighthouse third-party-summary reports fewer than 5 distinct third-party origins. Each origin costs a DNS lookup + TCP handshake + TLS negotiation - the FCP cost compounds.
Paste your homepage URL. Sentry runs PSI for mobile + desktop, pulls 28-day CrUX field FCP, and inspects Lighthouse's render-blocking, text-compression, font-display, preconnect, and third-party-summary diagnostics. No signup, instant results, always free.
Sentry fetches your site, runs every FCP 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 FCP 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.