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 decimal and the other way for any string input.
Get the gravatar.com globally recognized avatar for any email.
Check if the URL is banned and marked as safe/unsafe by Google.
Make sure your passwords are good enough.
Check for 301 & 302 redirects of a specific URL. It will check for up to 10 redirects.
Get & verify the meta tags of any website.
Get the web-host of a given website.