It's a very nice idea, but the validation rules are extremely limited.<p>Perhaps I'm wrong, but all of the rule options on the site look like they could have been implemented via regular expressions. Given the technical expertise of your intended customers, why not allow them to set a list of rules in the format: [regex, error-message], e.g.<p><pre><code> "^.{0,50}\n" "The subject should be 50 characters or under"
"^.+\n(.{0,72}\n)*$" "The body should have lines of 72 characters or under"
"^\p{Upper}" "The subject should be capitalized"</code></pre>