Wattspeed από Wattspeed

- Mobile-friendly test
- Google Lighthouse scores
- HTML5 validation
- Accessibility checker
- Mixed content & JSON-LD structured data snippet detection

and more...

- What web server is behind the URL?
- What Analytics tool is used to get visitor insights?
- What Marketing or Chat tools are used to convert the visitors?
- What Advertising network is running in order to sell ads?
- What CMS powers the forum, blog or the online shop?
- What CSS and JS frameworks are used to build that user interface?