diff --git a/.env.example b/.env.example
index 9372ce9..2b9577d 100644
--- a/.env.example
+++ b/.env.example
@@ -2,3 +2,7 @@ API_KEY=your_api_key
 API_SECRET_KEY=your_api_secret_key
 ACCESS_TOKEN=your_access_token
 ACCESS_TOKEN_SECRET=your_access_token_secret
+TWITTER_BACKEND=twitter
+XQUIK_API_KEY=your_xquik_api_key
+XQUIK_ACCOUNT=your_x_account_username
+XQUIK_API_BASE=https://xquik.com/api/v1
diff --git a/README.md b/README.md
index 7c867e6..0d07005 100644
--- a/README.md
+++ b/README.md
@@ -26,15 +26,15 @@ composer install
 ```
 
 ### Configuration
-#### Option 1: Using Environment Variables
+#### Option 1: Using Shell Environment Variables
 
-Rename the file .env.example to .env and update it with your Twitter API credentials:
+Export your credentials before running the script:
 
-```dotenv
-API_KEY=your_api_key
-API_SECRET_KEY=your_api_secret_key
-ACCESS_TOKEN=your_access_token
-ACCESS_TOKEN_SECRET=your_access_token_secret
+```bash
+export API_KEY=your_api_key
+export API_SECRET_KEY=your_api_secret_key
+export ACCESS_TOKEN=your_access_token
+export ACCESS_TOKEN_SECRET=your_access_token_secret
 ```
 
 #### Option 2: Using config.php
@@ -47,11 +47,35 @@ define('API_KEY', 'your_api_key');
 define('API_SECRET_KEY', 'your_api_secret_key');
 define('ACCESS_TOKEN', 'your_access_token');
 define('ACCESS_TOKEN_SECRET', 'your_access_token_secret');
+define('TWITTER_BACKEND', 'twitter');
+define('XQUIK_API_KEY', 'your_xquik_api_key');
+define('XQUIK_ACCOUNT', 'your_x_account_username');
+define('XQUIK_API_BASE', 'https://xquik.com/api/v1');
 ?>
 ```
 
+Environment variables override values from `config.php`.
+
 Note: For security reasons, ensure that config.php and .env are added to your .gitignore file and not committed to version control.
 
+### Optional: Posting with Xquik
+
+Set `TWITTER_BACKEND` to `xquik` to post through Xquik:
+
+```dotenv
+TWITTER_BACKEND=xquik
+XQUIK_API_KEY=your_xquik_api_key
+XQUIK_ACCOUNT=your_x_account_username
+XQUIK_API_BASE=https://xquik.com/api/v1
+```
+
+The script sends `account` and `text` to `POST /api/v1/x/tweets` with the
+`x-api-key` header. The default `twitter` backend continues to use X API v2
+with OAuth 1.0a.
+
+Xquik is an independent third-party service. Not affiliated with X Corp.
+"Twitter" and "X" are trademarks of X Corp.
+
 ### Customize Your Tweet
 
 Edit the post_tweet.php script to customize the tweet content:
diff --git a/config.php b/config.php
index 866b4ec..6b5466a 100644
--- a/config.php
+++ b/config.php
@@ -3,4 +3,8 @@
 define('API_SECRET_KEY', 'YOUR_API_SECRET_KEY');
 define('ACCESS_TOKEN', 'YOUR_ACCESS_TOKEN');
 define('ACCESS_TOKEN_SECRET', 'YOUR_ACCESS_TOKEN_SECRET');
+define('TWITTER_BACKEND', 'twitter');
+define('XQUIK_API_KEY', 'YOUR_XQUIK_API_KEY');
+define('XQUIK_ACCOUNT', 'YOUR_X_ACCOUNT_USERNAME');
+define('XQUIK_API_BASE', 'https://xquik.com/api/v1');
 ?>
diff --git a/post_tweet.php b/post_tweet.php
index ef67e0a..de9976d 100644
--- a/post_tweet.php
+++ b/post_tweet.php
@@ -6,25 +6,24 @@
 error_reporting(E_ALL);
 ini_set('display_errors', getenv('APP_DEBUG') ? '1' : '0');
 
-// Twitter API credentials
-if (!file_exists(__DIR__ . '/config.php')) {
-    fwrite(STDERR, "Error: config.php not found. Copy .env.example values into config.php.\n");
+// Optional file-based credentials. Environment variables override these values.
+if (file_exists(__DIR__ . '/config.php')) {
+    require_once __DIR__ . '/config.php';
+}
+
+$backend = strtolower(trim(getConfigValue('TWITTER_BACKEND', 'twitter')));
+if ($backend !== 'twitter' && $backend !== 'xquik') {
+    fwrite(STDERR, "Error: TWITTER_BACKEND must be twitter or xquik.\n");
     exit(1);
 }
-require_once __DIR__ . '/config.php';
-
-// Validate that credentials have been configured
-$credentials = [
-    'API_KEY' => API_KEY,
-    'API_SECRET_KEY' => API_SECRET_KEY,
-    'ACCESS_TOKEN' => ACCESS_TOKEN,
-    'ACCESS_TOKEN_SECRET' => ACCESS_TOKEN_SECRET,
-];
-foreach ($credentials as $name => $value) {
-    if (empty($value) || strpos($value, 'YOUR_') === 0) {
-        echo "Error: $name is not configured. Please update config.php with your actual credentials.\n";
-        exit(1);
-    }
+
+if ($backend === 'twitter') {
+    validateCredentials([
+        'API_KEY' => getConfigValue('API_KEY'),
+        'API_SECRET_KEY' => getConfigValue('API_SECRET_KEY'),
+        'ACCESS_TOKEN' => getConfigValue('ACCESS_TOKEN'),
+        'ACCESS_TOKEN_SECRET' => getConfigValue('ACCESS_TOKEN_SECRET'),
+    ]);
 }
 
 // The tweet content variables
@@ -54,16 +53,21 @@
     */
 }
 
+if ($backend === 'xquik') {
+    postTweetWithXquik($fullTweet);
+    exit(0);
+}
+
 // Twitter API endpoint for creating a tweet (API v2)
 $url = 'https://api.twitter.com/2/tweets';
 
 // OAuth parameters
 $oauth = [
-    'oauth_consumer_key' => API_KEY,
+    'oauth_consumer_key' => getConfigValue('API_KEY'),
     'oauth_nonce' => bin2hex(random_bytes(16)),
     'oauth_signature_method' => 'HMAC-SHA1',
     'oauth_timestamp' => time(),
-    'oauth_token' => ACCESS_TOKEN,
+    'oauth_token' => getConfigValue('ACCESS_TOKEN'),
     'oauth_version' => '1.0',
 ];
 
@@ -79,7 +83,10 @@
 $base_info = buildBaseString($url, 'POST', $signature_params);
 
 // Generate the composite signing key
-$composite_key = rawurlencode(API_SECRET_KEY) . '&' . rawurlencode(ACCESS_TOKEN_SECRET);
+$composite_key =
+    rawurlencode(getConfigValue('API_SECRET_KEY')) .
+    '&' .
+    rawurlencode(getConfigValue('ACCESS_TOKEN_SECRET'));
 
 // Generate the OAuth signature and add it to the OAuth parameters
 $oauth_signature = base64_encode(hash_hmac('sha1', $base_info, $composite_key, true));
@@ -107,8 +114,10 @@
 $http_status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
 $curl_err = $response === false ? curl_error($ch) : null;
 
-// Close cURL
-curl_close($ch);
+// PHP 8 releases cURL handles automatically. PHP 8.5 deprecates curl_close().
+if (PHP_VERSION_ID < 80000) {
+    curl_close($ch);
+}
 
 if ($response === false) {
     $error_message = "Failed to post tweet. cURL error: $curl_err\n";
@@ -148,6 +157,113 @@
 
     echo $error_message;
     logTwitterResponse($http_status, $error_message);
+    exit(1);
+}
+
+/**
+ * Reads a config value from the environment or config.php.
+ *
+ * @param string $name
+ * @param string $default
+ * @return string
+ */
+function getConfigValue($name, $default = '')
+{
+    $environmentValue = getenv($name);
+    if ($environmentValue !== false && $environmentValue !== '') {
+        return $environmentValue;
+    }
+
+    return defined($name) ? (string) constant($name) : $default;
+}
+
+/**
+ * Validates required credentials.
+ *
+ * @param array $credentials
+ * @return void
+ */
+function validateCredentials($credentials)
+{
+    foreach ($credentials as $name => $value) {
+        if (empty($value) || stripos($value, 'your_') === 0) {
+            fwrite(STDERR, "Error: $name is not configured.\n");
+            exit(1);
+        }
+    }
+}
+
+/**
+ * Posts a tweet through Xquik's REST API.
+ *
+ * @param string $fullTweet
+ * @return void
+ */
+function postTweetWithXquik($fullTweet)
+{
+    $apiKey = getConfigValue('XQUIK_API_KEY');
+    $account = getConfigValue('XQUIK_ACCOUNT');
+    validateCredentials([
+        'XQUIK_API_KEY' => $apiKey,
+        'XQUIK_ACCOUNT' => $account,
+    ]);
+
+    $apiBase = rtrim(getConfigValue('XQUIK_API_BASE', 'https://xquik.com/api/v1'), '/');
+    $postfields = json_encode([
+        'account' => $account,
+        'text' => $fullTweet,
+    ], JSON_UNESCAPED_UNICODE);
+    if ($postfields === false) {
+        fwrite(STDERR, "Error: Could not encode the Xquik request.\n");
+        exit(1);
+    }
+
+    $ch = curl_init();
+    if ($ch === false) {
+        fwrite(STDERR, "Error: Could not initialize cURL.\n");
+        exit(1);
+    }
+
+    curl_setopt_array($ch, [
+        CURLOPT_URL => $apiBase . '/x/tweets',
+        CURLOPT_POST => true,
+        CURLOPT_HTTPHEADER => [
+            'Content-Type: application/json',
+            'x-api-key: ' . $apiKey,
+        ],
+        CURLOPT_POSTFIELDS => $postfields,
+        CURLOPT_RETURNTRANSFER => true,
+    ]);
+
+    $response = curl_exec($ch);
+    $http_status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
+    $curl_err = $response === false ? curl_error($ch) : null;
+    if (PHP_VERSION_ID < 80000) {
+        curl_close($ch);
+    }
+
+    if ($response === false) {
+        $error_message = "Failed to post tweet with Xquik. cURL error: $curl_err\n";
+        fwrite(STDERR, $error_message);
+        logTwitterResponse($http_status, $error_message);
+        exit(1);
+    }
+
+    $response_data = json_decode($response, true);
+    if ($http_status >= 200 && $http_status < 300 && isset($response_data['tweetId'])) {
+        $success_message = "Tweet posted successfully with Xquik! Tweet ID: " . $response_data['tweetId'];
+        echo $success_message;
+        logTwitterResponse($http_status, $success_message);
+        return;
+    }
+
+    $error_message = "Failed to post tweet with Xquik. HTTP Status Code: $http_status\n";
+    if (is_array($response_data) && isset($response_data['message'])) {
+        $error_message .= "Message: " . $response_data['message'] . "\n";
+    }
+    fwrite(STDERR, $error_message);
+    logTwitterResponse($http_status, $error_message);
+    exit(1);
 }
 
 /**