Site Performance Checker by Strelva

Instant performance audit: Core Web Vitals, resource analysis, image optimization & load timing. Fast and private.

See what's slowing a page down, measured live from your own browser. One click, no signup, nothing leaves your device. What it measures: Core Web Vitals - Largest Contentful Paint (LCP) and Cumulative Layout Shift (CLS), read live via the browser's Performance API - CLS is calculated the way Google does it, using the session-window method, so it matches what you'd see in the field Resources - Measured page weight, broken down by scripts, styles, images, and fonts - Largest resources and a first-party vs third-party split - Honest labeling: cross-origin bytes the browser can't see are noted, not guessed Images - Oversized images caught by comparing their real resolution to their display size, so it works even for images served from a CDN - Missing lazy-loading and legacy image formats - Click any flagged image to highlight it on the page Who it's for: Site owners who want a fast site, freelancers doing quick performance checks, and developers spotting the heavy assets on a page. A note on honesty: A browser extension can measure a lot from a loaded page, but not everything (some server-side timing needs a lab tool). This checker reports what it can genuinely measure and clearly says when a number is partial, rather than showing a confident wrong figure. Privacy: All analysis runs locally in your browser. Nothing about the pages you check is sent to a server. No accounts, no tracking, no cookies. Free: Completely free, no premium tiers. For the full site report, visit https://strelva.com/audit?tool=mobile