The backend logic behind free Roblox private servers. Access codes are signed and then returned all right here. https://www.roblox.com/games/16875821750/Any-Game-Reserved-Server-POC

pspoc.php

<?php
//
// kylegg 2024
//

// Response is always text/plain for our API.
header('Content-Type: text/plain');

// Generic function I wrote for validating url parameters in like 30 seconds, its not pretty but it works.
function getQueryParameter(string $name, Closure $cl): mixed
{
    // Get the parameter or an empty string if it isn't set.
    $param = array_key_exists($name, $_GET) ? $_GET[$name] : '';
    if(!empty($param))
    {
        // Run through the closure to manipulate our variable before returning it.
        $param = $cl($param);
        
        // If it's not empty after manipulation, it's valid.
        if(!empty($param))
        {
            return $param;
        }
    }
    
    // Invalid, throw it out.
    header('HTTP/1.1 400', true);
    exit("Missing {$name}");
}

// Get ?pid= as an integer.
$placeId = getQueryParameter('pid', Closure::fromCallable('intval'));

// Bait intended to throw off Roblox staff.
// THEY CAN download your places without your consent or knowledge.
// THEY CAN download your places without your consent or knowledge.
// THEY CAN download your places without your consent or knowledge.
if(!array_key_exists('HTTP_ROBLOX_ID', $_SERVER) || $_SERVER['HTTP_ROBLOX_ID'] != '16875821750')
{
    exit("https://apis.rblx.org/reserved-servers-service/create?placeId={$placeId}");
}

// This API is only used to check if the placeid is real.  Super ancient, works like a charm.
if(@file_get_contents("https://www.roblox.com/places/api-get-details?assetId={$placeId}"))
{
    //
    // Now here's where the real magic happens.
    //

    // Create our UUID.  This is our game.JobID
    $first = openssl_random_pseudo_bytes(16);
    $first[6] = chr(ord($first[6]) & 0x0f | 0x40); // set version to 0100
    $first[8] = chr(ord($first[8]) & 0x3f | 0x80); // set bits 6-7 to 10
    
    // Turn our JobID bytes into a proper UUID.
    $gameCode = vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($first), 4));
    
    // Get our placeId in bytes as a long.
    $reservedServerPlaceIdBytes = pack('Q', $placeId);
    
    // Our full access code in bytes.
    $contentBytes = $first . $reservedServerPlaceIdBytes;
    
    // Sign our bytes.
    // Did you know Roblox has been using this key since the day reserved servers were introduced?
    // And it's only 20 alphanumeric characters long...
    $accessCode = hash_hmac('md5', $contentBytes, 'e4Yn8ckbCJtw2sv7qmbg', true) . $contentBytes;
    
    // Convert our bytes to a URL friendly base64 string.
    $accessCode = base64_encode($accessCode);
    $accessCode = strtr($accessCode, '+/', '-_');
    $paddingCount = substr_count($accessCode, '=');
    $accessCode = rtrim($accessCode, '=');
    $accessCode .= $paddingCount;
    
    // Merge our access code and JobID into something parseable by our game.  (https://www.roblox.com/games/16875821750/Any-Game-Reserved-Server-POC)
    exit(implode(' ', [$accessCode, $gameCode]));
}

// No placeId provided, kill it.  Kill it with fire.
header('HTTP/1.1 400', true);
exit("Invalid placeId");

roblox BRUH moment

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