wsclient.pl

use Mojo::UserAgent;

my $ua = Mojo::UserAgent->new;
$ua->websocket('ws://localhost:3000/echo' => sub {
  my $tx = pop;
  $tx->on(finish => sub  { Mojo::IOLoop->stop });
  $tx->on(message => sub {
    my ($tx, $message) = @_;
    print "$message\n";
  });
  $tx->send('Hi!');
});
Mojo::IOLoop->start;

wsserver.pl

use Mojolicious::Lite;

websocket '/echo' => sub {
  my $self = shift;
  $self->on(message => sub {
    my ($self, $message) = @_;
    $self->send("echo: $message");
  });
};

app->start('daemon');