emailtemplate is a Go package for loading and executing email templates. An email template is a directory which consists of a subject, HTML and text Go template file.
Your backend server is written in Go. It passes recipient data to Go templates which are then executed and used when sending mail.
However, you don't want to hand-code the email template parts. Most notably, you don't want to hand-code the HTML part because the tooling for writing HTML in Go templates is not as suitable as tooling in the frontend space. Further, HTML emails are a beast of their own and so using an external toolkit to do things like CSS classes to inline styles is desirable. So, instead, you generate the parts externally (perhaps using a frontend toolkit like React and friends).
emailtemplate lets you structure your email templates into a directory containing 3 parts, each of which are Go templates: subject.txt, html.html and text.txt. The directory name is used as the template name when fetching a particular template.
go test -race ./...