It really depends on your needs. I'm mostly used to the server side of things writing cyclic executives, so i'm not sure what event based options for clients are available ;-)

The couple of times i needed a websocket client, i did it "by hand" using Protocol::WebSocket::Frame after connecting via IO::Socket::SSL, because that works well enough for my own cyclic needs.

Connection is easy, unless the W3C has re-defined things yet again. Here's an untested(!) minimal cyclic executive (a "worker") based on some of my existing codebase. I didn't include all that much error handling here, though, to keep the code small.

use IO::Socket::SSL;
use Protocol::WebSocket::Frame;
use Carp;
use Time::HiRes qw(sleep);
use Data::Dumper;

# Connect to server
my $sock = IO::Socket::SSL->new(
                PeerHost => $self->{server},
                PeerPort => $self->{port},
                SSL_verify_mode => SSL_VERIFY_NONE,
            ) or croak($!);

binmode($sock);

# Switch to unblocking after the SSL initiation
$sock->blocking(0);

# Write the header
my $header =
    "GET /public/api/blablabla HTTP/1.1\r\n" .
    "Host: example.com\r\n" .
    "Upgrade: websocket\r\n" .
    "Connection: Upgrade\r\n" .
    "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n" .
    "Sec-WebSocket-Protocol: chat\r\n" .
    "Sec-WebSocket-Version: 13\r\n" .
    "Origin: https://cavac.at\r\n" .
    "\r\n";

$syswrite($sock, $header);

# "Parse" the return headers from the server by just skipping over it,
+ hoping for the best ;-)
syswrite($sock, $header);
my $line = "";
while(1) {
    my $char;
    sysread($sock, $char, 1);
    if(defined($char) && length($char)) {
        if($char eq "\r") {
            next;
        } elsif($char eq "\n") {
            if($line eq "") {
                # end of header
                last;
            } else {
                $line = "";
            }
        } else {
            $line .= $char;
        }
    } else {
        sleep(0.05); # wait a few microseconds for more data
    }
}

# Initiate the websocket frame handler
my $frame = Protocol::WebSocket::Frame->new(max_payload_size => 500 * 
+1024 * 1024, masked => 1);

# Send a frame
{
    my %request = (
        'request-type'  => 'HelloWorld',
        'message-id' => 'rand' . int(rand(1_000_000)),
        'other-stuff' => 'Hello Welt!',
    );
    my $outframe = $frame->new(buffer => encode_json(\%request), type 
+=> 'text', masked => 1)->to_bytes;
    syswrite($sock, $outframe);
}

# Handle messages from server
while(1) {
    # Read from socket and append data to the frame parser
    my $workCount = 0;
    while(1) {
        my $char;
        sysread($sock, $data, 1_000);
        last if(!defined($data) || !length($data));
        $frame->append($data);
        $workCount++;
    }

    # Parse and react to messages from server
    while(my $data = $frame->next_bytes) {
        my $msg = decode_json($data);
        print Dumper($msg); # Just print it out
    }

    if(1) { # Other cyclic work you need to do in the program
        # doSomeStuff();
        # $workCount++;

    }

    if(!$workCount) {
        # Nothing happened, just sleep a bit, try again later. Save on
+ CPU cycles
        sleep(0.05);
    }
}
[download]

Hope that helps.