Hey guys,

I've been looking for a more comprehensive approach to the problem of email normalization and came up with one that I believe surpasses all other attempts I've seen on GitHub.

It's a JavaScript package for Meteor, https://github.com/iDoRecall/email-normalize

Works for:

• gmail.com, googlemail.com and google.com - the only domains Google is known to use for incoming email
• Any domain hosted with Google Apps for Work
• FastMail and domains hosted with FastMail
• Microsoft's outlook.com, hotmail.com, live.com
• Yahoo! domains

PRs welcome.

Hi, there is a specific reason to duplicate the code in the 2 validation function? The Validate function does exactly what the FastValidation does plus the MX lookup. My 2 cents for the Validate function:

func Validate(email string) error {
	fastValidationErr := ValidateFast(email)
	if fastValidationErr != nil {
		return fastValidationErr
	}

	at := strings.LastIndex(email, "@")
	host := email[at+1:]

	switch host {
	case "localhost", "example.com":
		return nil
	}

	if _, err := net.LookupMX(host); err != nil {
		if _, err := net.LookupIP(host); err != nil {
			// Only fail if both MX and A records are missing - any of the
			// two is enough for an email to be deliverable
			return ErrUnresolvableHost
		}
	}

	return nil
}

As per subject. FastValidate misses some incorrectly formatted emails that Validate catches. I think it shouldn't be so.