For various reasons I prefer to remove the www part from my personal-use domains. Setting up Caddy to serve the site from just domain.com is as simple as:

domain.com {
    root /path/to/site/files
    # other directives
}

But this set-up doesn’t provide any way to redirect from www to non-www, meaning anyone who types www.domain.com into the address bar is out of luck. So what to do? Well, Caddy provides a redir directive. Combine with a new site directive and a placeholder like this:

# Original non-WWW site:
domain.com {
    root /path/to/site/files
    # other directives
}
# New, additional "site", for doing the redir
www.domain.com {
    redir domain.com{uri}
}