Monitor Core Web Vitals in Real-Time
Track LCP, FCP, TTFB, CLS, INP, and FID as you browse. Export metrics to JSON or CSV for analysis.
Core Web Vitals
example.comEverything You Need for Performance Monitoring
LightScout gives you instant visibility into Core Web Vitals as you browse, without complex setup or configuration
All 6 CWV Metrics
LCP, FCP, TTFB, CLS, INP, and FID tracked in real-time using the browser's Performance Observer API.
Visual Ratings
Color-coded Good, Needs Improvement, and Poor ratings based on Google's official thresholds.
Session Grouping
Pages automatically grouped by domain within your browsing session for easy comparison.
Export Options
Download metrics as JSON or CSV for spreadsheets, reports, and further analysis.
No Account Required
Works immediately after installation. No signup, no login, no configuration needed.
Privacy-First
All data stays in your browser. Nothing is sent to external servers. Complete privacy.
Core Web Vitals Explained
LCP - Largest Contentful Paint
Measures loading performance. Good: under 2.5s
FCP - First Contentful Paint
Time to first visible content. Good: under 1.8s
TTFB - Time to First Byte
Server response time. Good: under 800ms
CLS - Cumulative Layout Shift
Visual stability score. Good: under 0.1
INP - Interaction to Next Paint
Responsiveness metric. Good: under 200ms
FID - First Input Delay
Interactivity timing. Good: under 100ms
Built for Performance-Conscious Teams
Whether you're optimizing during development or reporting to clients, LightScout adapts to your workflow
For Developers
Performance Auditing During Development
Monitor Core Web Vitals as you build to catch performance issues early.
- Real-time feedback during development
- Compare metrics before and after changes
- Catch performance regressions instantly
For QA Teams
A/B Testing Performance Impact
Measure how new features affect Core Web Vitals across different page variants.
- Quantify performance differences between variants
- Export data for stakeholder reports
- Document performance regressions objectively
For Agencies
Competitive Benchmarking
Compare your client's sites against competitors with exportable metrics.
- Benchmark against industry competitors
- Create data-driven improvement proposals
- Track progress over time
For Consultants
Client Reporting with Exportable Metrics
Generate professional performance reports with CSV and JSON exports.
- Export metrics to spreadsheets
- Create visual reports for clients
- Track improvements over engagements
Ready to Monitor Your Core Web Vitals?
Start tracking performance metrics in seconds. No account required.
Add LightScout to Chrome - FreeFrequently Asked Questions
Everything you need to know about LightScout
Core Web Vitals are a set of metrics defined by Google that measure real-world user experience for loading performance (LCP), interactivity (FID, INP), and visual stability (CLS). They're important ranking factors for search and directly impact user experience.
LightScout tracks all 6 Core Web Vitals: LCP (Largest Contentful Paint), FCP (First Contentful Paint), TTFB (Time to First Byte), CLS (Cumulative Layout Shift), INP (Interaction to Next Paint), and FID (First Input Delay).
LightScout uses the browser's Performance Observer API to capture Core Web Vitals metrics in real-time as you browse. Metrics are displayed in a popup with color-coded ratings based on Google's official thresholds.
LightScout is designed to have minimal impact. It uses the same Performance Observer APIs that browsers use internally. The extension is lightweight and doesn't interfere with page loading or rendering.
All data stays local in your browser. LightScout never sends any data to external servers. Metrics are stored in browser memory during your session and cleared when you close the browser or click 'Clear Session'.
LightScout is available for Chrome and other Chromium-based browsers (Edge, Brave, etc.). Firefox support is planned for a future release.
Yes! LightScout supports exporting metrics as JSON or CSV files. This makes it easy to analyze data in spreadsheets, create reports, or integrate with other tools.
Green means 'Good' - the metric meets Google's recommended threshold. Yellow means 'Needs Improvement' - the metric is acceptable but could be better. Red means 'Poor' - the metric needs attention and may negatively impact user experience.
No! LightScout works immediately after installation with no signup, login, or configuration required. It's completely free with no premium tiers or hidden features.
For questions or issues, you can reach us at bobby@nodebridge.dev. We also have documentation available on our website.
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