Frequently Asked Questions

Website speed directly impacts your business success. Studies show that 53% of mobile users abandon sites that take longer than 3 seconds to load. Every second of delay can reduce conversions by up to 7%.

Beyond user experience, Google uses page speed as a ranking factor. Faster websites rank higher in search results, leading to more organic traffic and visibility.

Google has confirmed that page speed is a ranking factor for both desktop and mobile searches. The Core Web Vitals – which measure loading, interactivity, and visual stability – are part of Google's page experience signals.

Sites that perform poorly may be penalized in search rankings, while fast, well-optimized sites get a competitive advantage.

Google Lighthouse is an open-source, automated tool developed by Google to audit web pages. It runs directly in your browser (built into Chrome DevTools) or via command line, and generates a report on how well your page performs.

Lighthouse tests your page in a simulated environment and measures things like loading speed, accessibility, SEO basics, and adherence to web development best practices.

PageSpeed Insights (PSI) is Google's web-based tool that uses Lighthouse under the hood. When you enter a URL on pagespeed.web.dev, Google runs a Lighthouse audit on their servers and returns the results.

The key difference: PSI also includes real-world data from the Chrome User Experience Report (CrUX), showing how actual visitors experience your site. Lighthouse alone only provides lab data from simulated tests.

LighthouseRobot uses the official PageSpeed Insights API, which means you get the same Lighthouse scores you'd see on pagespeed.web.dev – but automated and tracked over time.

I chose the PSI API because it's reliable, free, and runs tests from Google's infrastructure rather than requiring my own testing servers. This keeps the service simple and the results consistent.

The Performance score measures how fast your page loads and becomes interactive. It's based on several metrics including:

• First Contentful Paint (FCP) – When the first content appears
• Largest Contentful Paint (LCP) – When the main content is visible
• Total Blocking Time (TBT) – How long the page is unresponsive
• Cumulative Layout Shift (CLS) – Visual stability during loading
• Speed Index – How quickly content is visually displayed

This is often the most volatile score as it depends on server response times, network conditions, and resource optimization.

The Accessibility score measures how usable your site is for people with disabilities. It checks for common issues like:

• Missing alt text on images
• Insufficient color contrast
• Missing form labels
• Incorrect heading hierarchy
• Missing ARIA attributes
• Keyboard navigation issues

A high accessibility score means your site is usable by more people and may also be legally required in many jurisdictions.

The Best Practices score checks whether your site follows modern web development standards and security practices:

• Using HTTPS
• Avoiding deprecated APIs
• No browser errors in the console
• Correct image aspect ratios
• Proper charset declaration
• Safe use of JavaScript

This score helps ensure your site is secure, reliable, and future-proof.

The SEO score checks basic search engine optimization factors that help your pages get discovered:

• Valid meta descriptions and titles
• Crawlable links
• Valid robots.txt
• Legible font sizes
• Proper use of hreflang tags
• Valid structured data

Note: This checks technical SEO basics, not content quality or backlinks.

LighthouseRobot uses Google's official color thresholds:

• Red (0-49) – Poor. Needs significant improvement.
• Yellow (50-89) – Needs improvement. Room for optimization.
• Green (90-100) – Good. Meets best practices.

LighthouseRobot uses Google's official PageSpeed Insights API to audit your websites. When an audit runs, I make three separate API calls and take the median score for each metric.

This "median-run strategy" significantly reduces score variability. A single Lighthouse test can vary by 10-15 points for the same page; taking the median reduces this to approximately 3 points.

All monitored sites are audited automatically every 8 hours – that's 3 times per day. Each audit runs 3 tests and takes the median score for stability, meaning 9 API calls per URL per day.

The Total Score displayed on LighthouseRobot is a simple average of all four Lighthouse scores (Performance + Accessibility + Best Practices + SEO) divided by 4.

This gives you a quick at-a-glance indicator of your overall website health, while the individual scores show you exactly where to focus improvements.

Lighthouse scores – especially Performance – can vary between runs due to:

• Server response time variations
• Network conditions
• Third-party scripts loading differently
• CDN cache states
• A/B tests or dynamic content

LighthouseRobot uses daily averages and median-run scoring to smooth out these fluctuations and give you meaningful trend data.

Currently, LighthouseRobot tests all sites using desktop settings. Desktop testing provides more stable and consistent scores.

Mobile testing with simulated throttling might be added in the future.

A Leaderboard is a collection of websites you want to compare. Your sites are automatically ranked by their Total Score, creating a competitive view of your portfolio's performance.

Each account can have one leaderboard with up to 10 monitored sites.

The Monitor detail page shows comprehensive data for a single website:

• Current scores (daily average)
• Historical score chart showing trends over time
• Core Web Vitals with visual range indicators
• Resource overview (total requests, page size)
• Individual audit history
• Quick actions like running a new audit or sharing

This view helps you track how your optimization efforts impact scores over time.

Core Web Vitals are Google's key metrics for measuring real-world user experience. LighthouseRobot displays these on each monitor's detail page with visual range bars showing where your site falls:

• Largest Contentful Paint (LCP) – How fast the main content loads. Good: under 2.5s
• First Contentful Paint (FCP) – When the first content appears. Good: under 1.8s
• Cumulative Layout Shift (CLS) – Visual stability during loading. Good: under 0.1
• Total Blocking Time (TBT) – How long the page is unresponsive. Good: under 200ms

These metrics directly impact your Google search rankings and user experience.

You can generate public share links for both your leaderboards and individual monitors. Anyone with the link can view the shared content without needing an account.

This is perfect for sharing performance reports with clients, posting comparisons on social media, embedding in presentations, or showcasing your optimization work.

Yes! When you enable sharing for a monitor, you get an embeddable SVG badge that shows all four Lighthouse scores as visual rings. The badge updates automatically with your latest scores.

Simply copy the HTML code from the Share modal and paste it into your website. The badge uses the official Lighthouse colors (green/orange/red) and links back to your public share page.

This is great for showing visitors that you care about performance, or for adding a trust signal to your portfolio.

Yes, by default all your data is private. Only you can see your dashboard, monitors, and audit history when logged in.

Share links are opt-in – you decide what to make public. You can deactivate share links at any time.

Just me! LighthouseRobot is a personal side project. I built it because I wanted a simple way to track Lighthouse scores for multiple websites without running manual tests all the time.

There's no company, no team, no investors – just one person who enjoys building useful tools.

Yes, completely free. No credit card required, no trial period, no hidden costs. I built this for myself and decided to share it. Enjoy!

Each account includes:

• 1 leaderboard
• Up to 10 monitored websites
• Daily automated audits (every 24 hours)
• Unlimited share links
• Full audit history