Using HTTP::Server::PSGI and Plack, you can build something like this.

plack_server.pl

use strict;
use warnings;
use HTTP::Server::PSGI;
use Plack::Request;
use Plack::Response;

my $app = sub {
    my $env = shift;
    my $req = Plack::Request->new($env);
    my $res = Plack::Response->new(200);

    # Read query parameters (?user=name)
    my $user = $req->parameters->{user} // 'Guest';

    # Read headers
    my $ua = $req->header('User-Agent');

    # Set a cookie
    $res->cookies->{session} = { value => 'abc123', path => '/' };

    # Create the response
    $res->content_type('text/html');
    $res->body("<h1>Hello $user</h1><p>Your browser: $ua</p>");

    return $res->finalize; # Generates the [status, headers, body] array
};

HTTP::Server::PSGI->new(port => 8080)->run($app);