Load time analyzed
directly in the browser + explained in an understandable way
Core Web Vitals, Lighthouse estimation, mobile simulation, accessibility, third-party analysis and more – without technical jargon and with real values directly in your browser window (mobile + desktop).
Lighthouse Score
Performance estimation like Google
Mobile-First Check
Viewport, touch targets, fonts
Accessibility
Alt text, labels, headings
Core Web Vitals
LCP, CLS, INP complete
Load Time Phases
TTFB → FCP → LCP → Load
Security Check
HTTPS, Headers, Mixed Content
CMS Detection
WordPress, Shopify, WooCommerce
Hosting Detection
Server, PHP version, CDN
Third-Party
External services grouped
Render-Blocking
Blocking resources
Asset Optimization
WebP Potential, Minify Check
Resource Hints
Preload, Prefetch, Preconnect
Font Loading
Google Fonts & font-display
JavaScript Execution
Parse Time & Heavy Scripts
Unused Code
CSS & JS Coverage
Cookies & Storage
Third-Party Cookie Analysis
Lazy Load Check
Images without lazy loading
Top 5 Tips
Prioritized recommendations
Email Report
With JSON attachment
Export
JSON + Customer Text
📋 Show complete feature list
🎯 Performance scores
- Lighthouse Performance Score (estimated)
- Your own VASTCOB Score with grade (A+ to F)
- Score breakdown by categories
📱 Mobile-First Analysis
- Viewport Meta Tag Check
- Touch target sizes (min. 44x44px)
- Font size check (min. 12px)
- Detect horizontal scrolling
- Analyze Zoom Behavior
- Mobile simulation: 3G, 4G, Fast 4G
♿ Accessibility (A11y)
- Find Images Without Alt Text
- Form fields without labels
- Heading structure (H1-H6)
- Document language (lang attribute)
- Skip-Link Check
- ARIA landmarks check
- Links with generic text
- Focus styles analysis
I'm ready to translate German text to English following your rules. Please provide the German text you'd like me to translate.
- HTTPS Check
- Detect Mixed Content
- Security headers (HSTS, CSP, X-Frame-Options)
- Identify Outdated Libraries
- Password fields on HTTP
- Insecure External Resources
🎨 Asset optimization
- WebP conversion potential
- Estimated savings in KB
- Check CSS minify status
- Check JS minify status
- Inline CSS/JS analysis
- Identify oversized images
📊 Core Web Vitals
- LCP (Largest Contentful Paint) with rating
- CLS (Cumulative Layout Shift) with rating
- INP (Interaction to Next Paint) with rating
- Color coding: Green/Yellow/Red
⏱️ Load time metrics
- TTFB (Time to First Byte)
- FCP (First Contentful Paint)
- Complete load time
- Visual timeline with phases
🔧 Technology detection
- CMS: WordPress, Joomla, Drupal, Shopify, Wix, Squarespace
- Shops: WooCommerce, Magento, PrestaShop, Shopware
- Page builders: Elementor, Divi, WPBakery, Oxygen, Bricks
- Caching: WP Rocket, LiteSpeed, W3TC, Autoptimize, NitroPack
- Version detection where available
🏠 Hosting & CDN
- Hosting provider detection
- CDN detection (Cloudflare, AWS, Vercel, etc.)
- Server header analysis
- TTFB rating by region
🎨 Critical CSS Analysis
- Detection of inline critical CSS
- Above-the-fold styles check
- Implementation recommendations
🔗 Resource Hints
- Preload Tags Analysis
- Prefetch tags analysis
- Preconnect tags analysis
- DNS Prefetch Check
- Missing Hints Recommendations
Font Loading
- Number of loaded fonts
- Google Fonts Detection
- Font-Display Check
- FOIT/FOUT risk assessment
⚡ JavaScript Analysis
- Estimated parse time
- Identify heavy scripts
- Long Tasks Detection
- Main Thread Blocking
🗑️ Unused code
- CSS Coverage Estimation
- JavaScript coverage estimation
- Savings Potential in KB
🍪 Storage Analysis
- Cookie count & size
- Identify third-party cookies
- localStorage Usage
- sessionStorage usage
🌐 Third-party analysis
- Grouping by Service Type
- Analytics (Google, Facebook, etc.)
- Advertising & Marketing
- Social Media Widgets
- CDNs & Libraries
- Load time impact per service
🚫 Render-Blocking
- Blocking CSS files
- Blocking JavaScript files
- Async/Defer recommendations
🖼️ Image optimization
- Images without lazy loading
- Above-the-fold images check
- Image size analysis
- WebP/AVIF recommendations
🛒 WooCommerce Special
- WooCommerce version detection
- AJAX cart fragment analysis
- Plugin Conflict Detection
- Shop-specific optimizations
⭐ Recommendations
- Top 5 prioritized tips
- Impact assessment (High/Medium/Low)
- Concrete action instructions
- Links to further resources
📤 Export & Sharing
- JSON export (complete data)
- Customer-friendly text copy
- Email sending with HTML report
- JSON attachment in email
🎨 User Interface
- 7 clear tabs
- Dark Mode Design
- Mini-badge for show/hide
- Responsive on all devices
- No installation required
Firefox installation: Right-click on the button → "Bookmark This Link"
Usage: Open any website and click on the bookmark.
Mini mode: The badge at the bottom right opens/closes the analysis panel.
What makes the Page Speed Performance Tool 4.0 by VASTCOB different?
Our tool analyzes your website directly in the browser – without external servers, without waiting time, without installation. Perfect for any website and any online shop, whether WordPress, Shopify, Wix or custom.
| Function | PSPT 4.0 | PageSpeed Insights | GTmetrix | Lighthouse |
|---|---|---|---|---|
| Free to use | ✓ | ✓ | Limited | ✓ |
| No installation required | ✓ | ✓ | ✓ | ✗ |
| Instant results (< 3 sec.) | ✓ | ✗ | ✗ | ✗ |
| Real user measurement (RUM) | ✓ | Lab Data | Lab Data | Lab Data |
| Mobile Simulation (3G/4G) | ✓ | ✓ | ✓ | ✓ |
| WooCommerce analysis | ✓ Specialized | ✗ | ✗ | ✗ |
| Plugin detection (WP Rocket, etc.) | ✓ | ✗ | ✗ | ✗ |
| CMS & Page Builder detection | ✓ | ✗ | Limited | ✗ |
| Third-party by category | ✓ Grouped | List | List | List |
| Cookie & storage analysis | ✓ | ✗ | ✗ | ✗ |
| Security Quick Check | ✓ | ✗ | ✗ | Limited |
| Understandable Recommendations | ✓ German | Technical | Technical | Technical |
| Email dispatch with report | ✓ + JSON | ✗ | Pro | ✗ |
| Data protection (no external servers) | ✓ | ✗ | ✗ | ✓ |
A performance budget is like a household budget for your website: you define how much your page may "consume" at most – in terms of file size, load time and requests. Our tool immediately shows you whether you are within budget or not.
4 predefined presets
Standard website, e-commerce, performance-optimized and generous – choose the budget that suits your website type.
10 important metrics
Total size, JavaScript, CSS, images, fonts, requests, third-party, LCP, TTFB and CLS – all important values at a glance.
Traffic Light System
Green (below 80%), Yellow (80-100%), Red (exceeded) – immediately recognize where action is needed.
Save settings
Your selected budget is stored in the browser and automatically used for the next analysis.
Available Budget Presets
For standard corporate websites and blogs
For WooCommerce, Shopify and online shops
For maximum speed
For complex websites with many features
Is the tool really free?
Is my data stored or shared with third parties?
Does the tool work on every website?
How accurate is the Lighthouse score?
Why are my values different from those in PageSpeed Insights?
What do LCP, CLS, and INP mean?
CLS (Cumulative Layout Shift): Measures visual stability (shifting elements) – should be under 0.1.
INP (Interaction to Next Paint): Response time for clicks/inputs – should be under 200ms.
Can I also use the tool for client websites?
How do I install the bookmarklet?
Firefox: Right-click on the button → "Bookmark This Link".
Safari: Right-click → "Add Link to Bookmarks".
Afterwards, you can click the bookmark on any website to start the analysis.
What is the difference compared to the browser DevTools performance analysis?
Does VASTCOB also offer professional optimization?
Do you need help with the optimization?
Our experts optimize WordPress websites and WooCommerce shops for maximum speed. Free initial consultation included.
Testing and improving website loading time – how to do it right
The loading time of a website now decides success or failure on the internet. Visitors expect a page to be fully loaded within two to three seconds. If it takes longer, many will leave – and Google downgrades slow pages in the ranking. With the VASTCOB PageSpeed Analyzer, you can check for free how fast your website really is and where there is potential for optimization.
What are Core Web Vitals and why are they important?
With the Core Web Vitals, Google has defined three key metrics that have had a direct influence on search engine ranking since 2021. LCP measures when the main content becomes visible. CLS assesses whether elements shift during loading. INP shows how quickly the page responds to user interactions. Our tool measures all three values directly in your browser and provides immediately understandable recommendations.
Loading time optimization for online shops
Especially for online shops such as WooCommerce, Shopify or Magento, performance is crucial. Every additional second of loading time demonstrably costs revenue. The VASTCOB tool automatically recognizes your shop system and provides specific tips for optimization. For WooCommerce, for example, we analyze the Cart Fragment feature, which is often responsible for performance problems.
Measure Mobile Performance
Over 60 percent of all website visits are made on mobile devices today. Google has used Mobile-First Indexing for years – the mobile version of your website determines the ranking. Our tool simulates various mobile connections and shows how long your page takes to load on 3G, 4G or fast LTE. This way you can identify problems before your visitors notice them.
Third-party scripts under control
Tracking pixels, chat widgets, ads and social media buttons: External scripts massively slow down many websites. The PageSpeed Analyzer groups all third-party requests clearly by category and shows their influence on loading time. This allows you to make an informed decision about which services are really necessary and which can be omitted.
Identify render-blocking resources
CSS and JavaScript files in the head section block the rendering of the page. Our tool finds these resources and shows concrete solutions: Which scripts can be loaded with defer or async? Where is Critical CSS missing? Which stylesheets could be loaded later? These optimizations often improve the First Contentful Paint by several seconds.
Check image optimization
On most websites, images make up over half of the data volume. The Analyzer checks whether Lazy Loading is correctly implemented, whether modern formats such as WebP or AVIF are used and whether responsive image sizes are set with srcset. If optimization is missing, we immediately show which images are affected.
Privacy-friendly analytics
Unlike PageSpeed Insights or GTmetrix, our tool does not send any data to external servers. The complete analysis runs locally in your browser. This makes the VASTCOB Analyzer not only faster, but also compliant with data protection. Ideal for websites with sensitive content or strict compliance requirements.
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