Alexa.com is built with the following tech stack:
Mobile
Viewport Meta
This page uses the viewport meta tag which means the content may be optimized for mobile content.
Document Standards
HTML5 DocType
The DOCTYPE is a required preamble for HTML5 websites.
HTML 5 Specific Tags
This page contains tags that are specific to an HTML 5 implementation.
Content Type Options
Used to disable MIME-sniffing for a particular HTTP response.