Welcome to the go-mail documentation
go-mail is an easy to use Go library for formating and sending mails. It uses idiomatic Go style and follows best practice with sane defaults. The library only dependends on the Go Standard Library.
go-mail works like a programatic email client and provides lots of methods and functionalities you would consider standard in a MUA.
Feature highlights
Standard Library dependant
go-mail does not require any third-party modules and only runs on the Go standard library
Modern, idiomatic Go
We are using modern and idiotmatic Go standards with this library and follow state-of-the-art best practices with sane defaults
Full TLS support
go-mail supports implicit STARTTLS with different policies as well as explicit SSL/TLS for connections to sending mail servers
Contexts
We make use of Go contexts for better control flow and timeout/cancelation handling
SMTP Authentication
Support for three common SMTP authentication mechanisms (LOGIN, PLAIN, CRAM-MD5) as well as custom authentications.
Mail address validation
go-mail follows RFC5322 and validates the provided mail addresses
Common mail header support
go-mail brings generators for lots of common mail headers (Message-ID, Date, Bulk-Precedence, Priority, etc.)
Connection reusing
You can send mulitple mails over the same SMTP connection
Attachments/Embeds
Full support for attachments and inline embeds from different sources (local file system, io.Reader or embed.FS)
Encodings and content types
go-mail supports different encondings and content types out of the box
Middlewares
Middleware support for 3rd-party libraries to alter mail message to their need
Sendmail and file storage
Support for sending mail messages through a local sendmail installation as well as output to
local files (e. g. as .eml files to disk to open them in a MUA)
MDNs and DSNs
go-mail brings support for requestng MDNs (RFC 8098) and DSNs (RFC 1891)
Template support
Support for Go’s html/template and text/template (as message body, alternative part or attachment/emebed)
DKIM support
DKIM signature support via the go-mail-middlware/dkim middleware
Debug logging
Support for the SMTP client to log any SMTP communication to STDERR for debug purposes
Custom delivery errors
With the SendError type the user is able to get detailed information about delivery errors
including if the error is of temporary nature or not
Support
We have a support and general discussion channel on Discord. Find us at: #go-mail