examples/singlefile.pl
#!/usr/bin/env perl
use Dancer2;
 
get '/' => sub {
    return 'Hello World';
};

dance;

$ perl singlefile.pl
>> Dancer2 v0.161000 server 1443 listening on http://0.0.0.0:3000
$ plackup -r singlefile.pl
Watching ./lib singlefile.pl for file updates.
HTTP::Server::PSGI: Accepting connections at http://0:5000/