# go-smtp [![Go Reference](https://pkg.go.dev/badge/github.com/emersion/go-smtp.svg)](https://pkg.go.dev/github.com/emersion/go-smtp) [![builds.sr.ht status](https://builds.sr.ht/~emersion/go-smtp/commits.svg)](https://builds.sr.ht/~emersion/go-smtp/commits?) 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. ## Licence MIT [RFC 5321]: https://tools.ietf.org/html/rfc5321 [AUTH]: https://tools.ietf.org/html/rfc4954 [PIPELINING]: https://tools.ietf.org/html/rfc2920 [LMTP]: https://tools.ietf.org/html/rfc2033