Owl Web Diagnostic

Check errors and performance on the page you're viewing.

Stop juggling the Console, Network tab and Lighthouse. See what's broken on any page in one glance. Owl Web Diagnostic watches the page from the moment it loads and puts everything that matters into one clean glass panel, ranked by what's actually wrong instead of dumped as raw logs. Open the page. See the problem. Copy the report. Done. WHAT YOU GET 🩺 OVERVIEW: one clear verdict A single health label (Healthy, Needs attention or Critical) and the top issues ranked by impact: unhandled errors first, then failed requests, then red Core Web Vitals, down to warnings last. Click any issue to jump straight to it. 🐛 ERRORS: no more 100 duplicate rows Console errors, uncaught exceptions and unhandled promise rejections, grouped by message with counts. Common patterns (CORS/CSP blocks, null reference errors, failed fetches, chunk-load failures and more) come with a plain-English explanation of what probably went wrong and what to try. It's all worked out locally. Nothing is sent anywhere. 🌐 REQUESTS: problems flagged automatically Every 4xx, 5xx and network error is caught for you. Slow requests are tagged with why they're slow (DNS, connection, server or download). Duplicate GET calls show a ×N count. One click copies any request as a ready-to-run cURL command. ⚡ VITALS: live, no Lighthouse run needed LCP, INP, CLS, FCP and TTFB, measured live against Google's thresholds. 👀 FLOATING COUNTER: problems you can't miss A small badge shows live error, failed and slow counts, even with the panel closed. You'll notice when something's off without opening anything. 📋 COPY REPORT: bug tickets in one click The page's findings as clean Markdown, ready to paste into a ticket or a Slack thread. BUILT FOR • Frontend and full-stack developers who want answers faster • QA engineers who need clear, shareable bug evidence • Product owners and testers who spot "Critical: 6 problems" and can hand it straight to a developer • Anyone checking a page they didn't build You don't have to be the one who fixes it to flag it. 🔒 PRIVATE BY DESIGN Everything runs locally in your browser. No account, no analytics, no servers. Nothing ever leaves your device. Values that look like passwords, tokens or cookies are redacted before they're shown or stored. 💚 FREE, FOR REAL No ads, nothing paid, nothing gated. Install it, open the page you're working on, and see what it has already found.