An elegant MIME mail library with support for attachments

A simple, easy to use email library for Go (golang).

Full attachment support (attach anything that implements io.Reader)
Send to multiple addresses at the same time, including BCC addresses.
Supports composing multi-part messages (HTML and plain text emails for older clients)
Write templates directly to the email body (implements io.Writer for convenience)
Production ready - several million emails sent in a production environment
SMTP over TLS support, with automatic STARTTLS upgrades for plaintext connections

Installation

If you're using go mod:

go get -v github.com/domodwyer/mailyak/v3

Or with GOPATH:

go get -v github.com/domodwyer/mailyak

Usage

// Create a new email - specify the SMTP host:port and auth (if needed)
mail := mailyak.New("mail.host.com:25", smtp.PlainAuth("", "user", "pass", "mail.host.com"))

mail.To("dom@itsallbroken.com")
mail.From("jsmith@example.com")
mail.FromName("Bananas for Friends")

mail.Subject("Business proposition")

// mail.HTML() and mail.Plain() implement io.Writer, so you can do handy things like
// parse a template directly into the email body
if err := t.ExecuteTemplate(mail.HTML(), "htmlEmail", data); err != nil {
    panic(" 💣 ")
}

// Or set the body using a string setter
mail.Plain().Set("Get a real email client")

// And you're done! 
if err := mail.Send(); err != nil {
    panic(" 💣 ")
}

To send an attachment:

mail := mailyak.New("mail.host.com:25", smtp.PlainAuth("", "user", "pass", "mail.host.com"))

mail.To("dom@itsallbroken.com")
mail.From("oops@itsallbroken.com")
mail.Subject("I am a teapot")
mail.HTML().Set("Don't panic")

// input can be a bytes.Buffer, os.File, os.Stdin, etc.
// call multiple times to attach multiple files
mail.Attach("filename.txt", &input)

if err := mail.Send(); err != nil {
    panic(" 💣 ")
}

Notes

Why "MailYak"? Because "MailyMcMailFace" is annoyingly long to type.
You can use a single instance of mailyak to send multiple emails after changing the to/body/whatever fields, avoiding unnecessary allocation/GC pressure.
Attachments are read when you call Send() to prevent holding onto multiple copies of the attachment in memory (source and email) - this means changing the attachment data between calling Attach() and Send() will change what's emailed out!
For your own sanity you should vendor this, and any other libraries when going into production.

ctengiz/mailyak

Installation

Usage

Notes