mailck - SMTP mail validation

golang library for email validation

This library allows you to check if an email address is realy valid:

• Syntax check
• Blacklist of disposable mailservers (e.g. mailinator.com)
• SMTP mailbox check

Preconditions

Make sure, that the ip address you are calling from is not black listed. This is e.g. the case if the ip is a dynamic IP. Also make sure, that you have a correct reverse dns lookup for your ip address, matching the hostname of your from adress. Alternatively use a SPF DNS record entry matching the host part of the from address.

In case of a blacklisting, the target mailserver may respond with an SMTP 554 or just let you run into a timout.

Usage

Do all checks at once:

result, _ := mailck.Check("noreply@mancke.net", "foo@example.com")
switch {

  case result.IsValid():
  // valid!
  // the mailserver accepts mails for this mailbox.

  case result.IsError():
  // something went wrong in the smtp communication
  // we can't say for sure if the address is valid or not

  case result.IsInvalid():
  // invalid for some reason
  // the reason is contained in result.ResultDetail
  // or we can check for different reasons:
  switch (result) {
    case mailck.InvalidDomain:
    // domain is invalid
    case mailck.InvalidSyntax:
    // e-mail address syntax is invalid
  }
}

License

MIT Licensed