go-emailaddress

go-emailaddress is a tiny Go library for finding, parsing and validating email addresses. This library is tested for Go v1.9 and above.

Note that there is no such thing as perfect email address validation other than sending an actual email (ie. with a confirmation token). This library however checks if the email format conforms to the spec and if the host (domain) is actually able to receive emails. You can also use this library to find emails in a byte array. This package was created as similar packages don't seem to be maintained anymore (ie contain bugs with pull requests still open), and/or use wrong local validation.

Usage

go get -u github.com/mcnijman/go-emailaddress

Parsing and local validation

Parse and validate the email locally using RFC 5322 regex, note that when err == nil it doesn't necessarily mean the email address actually exists.

import "github.com/mcnijman/go-emailaddress"

email, err := emailaddress.Parse("foo@bar.com")
if err != nil {
    fmt.Println("invalid email")
}

fmt.Println(email.LocalPart) // foo
fmt.Println(email.Domain) // bar.com
fmt.Println(email) // foo@bar.com
fmt.Println(email.String()) // foo@bar.com

Validating the host

Host validation will first attempt to resolve the domain and then verify if we can start a mail transaction with the host. This is relatively slow as it will contact the host several times. Note that when err == nil it doesn't necessarily mean the email address actually exists.

import "github.com/mcnijman/go-emailaddress"

email, err := emailaddress.Parse("foo@bar.com")
if err != nil {
    fmt.Println("invalid email")
}

err := email.ValidateHost()
if err != nil {
    fmt.Println("invalid host")
}

Validating that the publix suffix is ICANN managed

Whether the public suffix is managed by the Internet Corporation for Assigned Names and Numbers. If not an error is returned and the public suffix is privately managed. For example, foo.org and foo.co.uk are ICANN domains, foo.dyndns.org and foo.blogspot.co.uk are private domains. More information on publix suffixes here.

import "github.com/mcnijman/go-emailaddress"

email, err := emailaddress.Parse("foo@bar.com")
if err != nil {
    fmt.Println("invalid email")
}

err := email.ValidateIcanSuffix()
if err != nil {
    fmt.Println("not an icann suffix")
}

Finding emails

This will look for emails in a byte array (ie text or an html response).

import "github.com/mcnijman/go-emailaddress"

text := []byte(`Send me an email at foo@bar.com or foo@domain.fakesuffix.`)
validateHost := false

emails := emailaddress.Find(text, validateHost)

for _, e := range emails {
    fmt.Println(e)
}
// foo@bar.com
// foo@domain.fakesuffix

As RFC 5322 is really broad this method will likely match images and urls that contain the '@' character (ie. !--logo@2x.png). For more reliable results, you can use the following method.

import "github.com/mcnijman/go-emailaddress"

text := []byte(`Send me an email at foo@domain.com or foo@domain.fakesuffix.`)
validateHost := false

emails := emailaddress.FindWithIcannSuffix(text, validateHost)

for _, e := range emails {
    fmt.Println(e)
}
// foo@bar.com

Versioning

This library uses semantic versioning 2.0.0.

License

This library is distributed under the MIT license found in the LICENSE file.