Convert text to binary and the other way for any string input.
Convert text to hexadecimal and the other way for any string input.
Convert text to ascii and the other way for any string input.
Convert text to octal and the other way for any string input.
Get the gravatar.com globally recognized avatar for any email.
Extract email addresses from any kind of text content.
Check if the URL is banned and marked as safe/unsafe by Google.
Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
Make sure your passwords are good enough.
Get all possible details about a domain name.