Get approximate IP details.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Get all possible details about an SSL certificate.
Get all possible details about a domain name.
Ping a website, server or port..
Extract email addresses from any kind of text content.
Convert markdown snippets to raw HTML code.
Take an IP and try to look for the domain/host associated with it.
Convert forum type bbcode snippets to raw HTML code.
Check if the URL is cached or not by Google.
Validate JSON content and make it looks good.