Lighthouse is Google's open-source tool for auditing web pages. RankPrompt integrates Lighthouse to give you detailed performance insights without leaving your dashboard.
How fast your page loads and becomes interactive:
Metric | What It Measures | Good Value |
LCP | Largest Contentful Paint—main content visibility | ≤ 2.5s |
FCP | First Contentful Paint—first render | ≤ 1.8s |
TBT | Total Blocking Time—interactivity delay | ≤ 200ms |
CLS | Cumulative Layout Shift—visual stability | ≤ 0.1 |
TTFB | Time to First Byte—server response | ≤ 800ms |
How usable your page is for people with disabilities:
Color contrast ratios
Keyboard navigation
Screen reader compatibility
ARIA labels and roles
Image alt text
Security and modern web standards:
HTTPS usage
No vulnerable JavaScript libraries
Console errors
Image aspect ratios
Document type declarations
Search engine optimization factors:
Meta descriptions
Title tags
Crawlable links
Mobile friendliness
Valid robots.txt
From the sidebar, click SEO Audits → Lighthouse Audit.
Use the dropdown to select a tracked page:
Shows all pages you've added
Displays page URL and label
If you need to add a page, click Add Page.
Click Run Lighthouse Audit:
Audit takes 30-60 seconds
Shows loading state while processing
Results appear when complete
Four score cards show your ratings:
Score | Color | Meaning |
90-100 | Green | Good performance |
50-89 | Orange | Needs improvement |
0-49 | Red | Poor—needs attention |
Below the scores, see detailed metrics:
Each metric shows its current value
Color-coded by good/needs improvement/poor
Hover for thresholds and explanations
Expandable list of specific issues found:
Click any issue to see details
Shows impact level (high/medium/low)
Provides recommendations for fixing
Re-run audits when:
You've made site changes
Checking if fixes worked
Regular monitoring schedule
Each Lighthouse audit costs 5 credits.
Click Audit History to see previous audits:
Date and time of each audit
Score summary badges
Click to view full results
Use history to track progress:
Did your score improve after changes?
Any regressions to investigate?
Trend direction over weeks/months
To remove an audit from history:
Expand the Audit History section
Click the trash icon next to the audit
Confirm deletion
Issue | Solution |
Large images | Compress and resize images |
Slow server response | Optimize hosting, use CDN |
Render-blocking resources | Defer non-critical CSS/JS |
Too much JavaScript | Code splitting, lazy loading |
No text compression | Enable GZIP on server |
Issue | Solution |
Missing alt text | Add alt attributes to images |
Low color contrast | Increase contrast ratio |
Missing form labels | Add labels to form fields |
No skip link | Add "skip to content" link |
Missing ARIA | Add appropriate ARIA attributes |
Issue | Solution |
No HTTPS | Install SSL certificate |
Vulnerable libraries | Update JavaScript dependencies |
Console errors | Fix JavaScript errors |
Bad image ratios | Set explicit width/height |
Issue | Solution |
Missing meta description | Add meta description tag |
Title too long/short | Optimize title length (50-60 chars) |
Non-crawlable links | Use standard anchor tags |
No viewport meta | Add responsive viewport tag |
Lighthouse audits simulate a mobile device by default. This is intentional:
Google uses mobile-first indexing
Mobile performance is typically worse
Fixing mobile usually fixes desktop too
Data Type | Description |
Lab Data | Simulated test (what Lighthouse provides) |
Field Data | Real user data (from Chrome UX Report) |
RankPrompt shows lab data. Field data (when available) provides additional context.
Causes:
Page not accessible
Page blocked Lighthouse
Timeout during audit
Solutions:
Verify page is publicly accessible
Check for bot-blocking security
Try again (transient issues)
Normal variation of ±5 points is expected due to:
Network variability
Server response times
Third-party scripts loading
If variance is larger, investigate caching or server issues.
Causes:
Heavy JavaScript frameworks
Many third-party scripts
Large hero images
Solution:
Focus on Core Web Vitals first
Optimize largest impact areas
Consider user experience trade-offs
Run weekly audits at minimum
Audit after major site changes
Track trends over time
Fix high-impact issues first
Focus on Core Web Vitals
Don't chase perfect scores at usability's expense
90+ is excellent but not always achievable
70-80 range is good for complex sites
Improvement matters more than absolute score
Technical SEO Audit - Check robots.txt, sitemap, and more
Competitor SEO Comparison - Compare against competitors
If you have questions about Lighthouse audits, contact us at [email protected].
