See the installation page for details on installing in multiple environments.
The versions page lists every released version of Swaks, complete with changelogs and download links.
The reference documentation from the latest release, which includes quick-start examples, is available as plain text and rendered. The documentation from each release is available from the versions page. There is also an Occasionally Asked Questions document.
The Swaks source code is available at https://github.com/jetmore/swaks.