validate/email.go

package validate

import (
	"net/mail"
)

var (
	ErrInvalidEmail = NewError("invalid email address")
)

// Email validates an email address using net/mail.ParseAddress.
//
// Only a bare address is accepted (alice@example.com). Anything with a
// display name, angle brackets, a comment, or trailing content is rejected,
// as is a list of addresses. Note that ParseAddress does not require the
// domain to have a dot, so "alice@localhost" is considered valid; layer on
// Match or a DNS check if you need to be stricter.
func Email(value string) error {
	addr, err := mail.ParseAddress(value)
	if err != nil || addr.Name != "" || addr.Address != value {
		return ErrInvalidEmail
	}

	return nil
}