EmailAddressValidator

A Ruby library to help you validate e-mail addresses

Like any data, an e-mail address that you accept from a user cannot just be accepted at face value, it needs to be validated. It's non-trivial to do this, though -- not only do you have to make sure that it is formatted correctly (and this is harder than it first appears, as the rules for what constitute a valid e-mail address aren't simple), you also have to make sure that the e-mail address will actually receive mail.

The EmailAddressValidator class tries, as much as possible without actually delivering an e-mail, to validate that an e-mail address is valid and will accept e-mail. It does this by regex validation, looking up the MXes for a domain, and making a delivery attempt.

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