emersion/go-smtp

📤 An SMTP library for Go clients and servers

Go

2,053

350 commits

updated Sep 17, 2026

See the code

README

go-smtp

Go Reference

An ESMTP client and server library written in Go.

Features

  • ESMTP client & server implementing RFC 5321
  • Support for additional SMTP extensions such as AUTH and PIPELINING
  • UTF-8 support for subject and message
  • LMTP support

Relationship with net/smtp

The Go standard library provides a SMTP client implementation in net/smtp. However net/smtp is frozen: it's not getting any new features. go-smtp provides a server implementation and a number of client improvements.

Contributing

See CONTRIBUTING.md for contribution guidelines.

Licence

MIT

client
esmtp
lmtp
mail
server
smtp

emersion/go-smtp

📤 An SMTP library for Go clients and servers

Go

2,053

350 commits

updated Sep 17, 2026

See the code

README

go-smtp

Go Reference

An ESMTP client and server library written in Go.

Features

  • ESMTP client & server implementing RFC 5321
  • Support for additional SMTP extensions such as AUTH and PIPELINING
  • UTF-8 support for subject and message
  • LMTP support

Relationship with net/smtp

The Go standard library provides a SMTP client implementation in net/smtp. However net/smtp is frozen: it's not getting any new features. go-smtp provides a server implementation and a number of client improvements.

Contributing

See CONTRIBUTING.md for contribution guidelines.

Licence

MIT

client
esmtp
lmtp
mail
server
smtp

Significant stargazers

(top 24 of 25)

Dmitri Shuralyov

2,508 followers · starred Mar 2024

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1,726 followers · starred Jul 2020

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106 followers · starred Feb 2024

Michael Scherbakow

42 followers · starred Jul 2023