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Package mailyak provides a simple interface for generating MIME compliant emails, and optionally sending them over SMTP. Both plain-text and HTML email body content is supported, and their types implement io.Writer allowing easy composition directly from templating engines, etc. Attachments are fully supported including inline attachments, with anything that implements io.Reader suitable as a source (like files on disk, in-memory buffers, etc). The raw MIME content can be retrieved using MimeBuf(), typically used with an API service such as Amazon SES that does not require using an SMTP interface. MailYak supports both plain-text SMTP (which is automatically upgraded to a secure connection with STARTTLS if supported by the SMTP server) and explicit TLS connections.


Version published


Status GoDoc

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


If you're using go mod:

go get -v

Or with GOPATH:

go get -v


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

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("", smtp.PlainAuth("", "user", "pass", ""))

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(" 💣 ")


  • 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.

Maintenance Status

This library is fully maintained.

The (relatively) small API/scope and many years spent maturing means it doesn't receive frequent code changes any more. Bug fixes are definitely accepted (and appreciated!), and you can consider this a stable and maintained library.


Last updated on 03 Aug 2023

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