Minify your HTML by removing all the unnecessary characters.
Minify your JS by removing all the unnecessary characters.
Get all the HTTP headers that an URL returns for a typical GET request.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get all possible details about a domain name.
Extract email addresses from any kind of text content.
Get approximate IP details.
Check whether or not a website is using the new HTTP/2 protocol or not.