diff --git a/src/LaunchDarkly/EventProcessor.php b/src/LaunchDarkly/EventProcessor.php
new file mode 100644
index 000000000..823865c1e
--- /dev/null
+++ b/src/LaunchDarkly/EventProcessor.php
@@ -0,0 +1,146 @@
+<?php
+namespace LaunchDarkly;
+
+/**
+ * @internal
+ */
+class EventProcessor {
+
+  private $_apiKey;
+  private $_queue;
+  private $_capacity;
+  private $_timeout;
+  private $_socket_failed;
+  private $_host;
+  private $_port;
+  private $_ssl;
+
+  public function __construct($apiKey, $options = []) {
+    $this->_apiKey = $apiKey;
+    if (!isset($options['base_uri'])) {
+        $this->_host = 'app.launchdarkly.com';
+        $this->_port = 443;
+        $this->_ssl = true;
+    } 
+    else {
+        $url = parse_url($options['base_uri']);
+        $this->_host = $url['host'];
+        $this->_ssl = $url['scheme'] === 'https';
+        if (isset($url['port'])) {
+          $this->_port = $url['port'];
+        } 
+        else {
+          $this->_port = $this->_ssl ? 443 : 80;
+        }
+    }
+
+    $this->_capacity = $options['capacity'];
+    $this->_timeout = $options['timeout'];
+
+    $this->_queue = array(); 
+  }
+
+  public function __destruct() {
+    $this->flush();
+  }
+
+  public function sendEvent($event) {
+    return $this->enqueue($event);
+  }
+
+  public function enqueue($event) {
+    if (count($this->_queue) > $this->_capacity) {
+      return false;
+    }
+
+    array_push($this->_queue, $event);
+
+    return true;
+  }
+
+  protected function flush() {
+    $socket = $this->createSocket();
+    
+    if (!$socket) {
+      error_log("LaunchDarkly unable to open socket");
+      return;
+    }
+    $payload = json_encode($this->_queue);
+
+    $body = $this->createBody($payload);
+
+    return $this->makeRequest($socket, $body);
+  }
+
+  private function createSocket() {
+    if ($this->_socket_failed) {
+      return false;
+    }
+
+    $protocol = $this->_ssl ? "ssl" : "tcp";
+  
+    try {
+
+      $socket = @pfsockopen($protocol . "://" . $this->_host, $this->_port, $errno, $errstr, $this->_timeout);
+
+      if ($errno != 0) {
+        $this->_socket_failed = true;
+        return false;
+      }
+
+      return $socket;
+    } catch (Exception $e) {
+      error_log("LaunchDarkly caught $e");
+      $this->socket_failed = true;
+      return false;
+    }
+  }
+
+  private function createBody($content) {
+    $req = "";
+    $req.= "POST /api/events/bulk HTTP/1.1\r\n";
+    $req.= "Host: " . $this->_host . "\r\n";
+    $req.= "Content-Type: application/json\r\n";
+    $req.= "Authorization: api_key " . $this->_apiKey . "\r\n";
+    $req.= "User-Agent: PHPClient/" . LDClient::VERSION . "\r\n";
+    $req.= "Accept: application/json\r\n";
+    $req.= "Content-length: " . strlen($content) . "\r\n";
+    $req.= "\r\n";
+    $req.= $content;
+    return $req;
+  }
+
+  private function makeRequest($socket, $req, $retry = true) {
+    $bytes_written = 0;
+    $bytes_total = strlen($req);
+    $closed = false;
+
+    while (!$closed && $bytes_written < $bytes_total) {
+      try {
+        $written = @fwrite($socket, substr($req, $bytes_written));
+      } catch (Exception $e) {
+        error_log("LaunchDarkly caught $e");
+        $closed = true;
+      }
+      if (!isset($written) || !$written) {
+        $closed = true;
+      } else {
+        $bytes_written += $written;
+      }
+    }
+
+    if ($closed) {
+      fclose($socket);
+      if ($retry) {
+        error_log("LaunchDarkly retrying send");
+        $socket = $this->createSocket();
+        if ($socket) return $this->makeRequest($socket, $req, false);
+      }
+      return false;
+    }
+
+    return true;
+  }
+
+
+}
\ No newline at end of file
diff --git a/src/LaunchDarkly/LDClient.php b/src/LaunchDarkly/LDClient.php
index 77c3c43ac..b1a6178d6 100644
--- a/src/LaunchDarkly/LDClient.php
+++ b/src/LaunchDarkly/LDClient.php
@@ -14,6 +14,7 @@ class LDClient {
     protected $_apiKey;
     protected $_baseUri;
     protected $_client;
+    protected $_eventProcessor;
 
     /**
      * Creates a new client instance that connects to LaunchDarkly.
@@ -29,7 +30,8 @@ public function __construct($apiKey, $options = []) {
         $this->_apiKey = $apiKey;
         if (!isset($options['base_uri'])) {
             $this->_baseUri = self::DEFAULT_BASE_URI;
-        } else {
+        } 
+        else {
             $this->_baseUri = rtrim($options['base_uri'], '/');
         }
         if (!isset($options['timeout'])) {
@@ -39,6 +41,12 @@ public function __construct($apiKey, $options = []) {
             $options['connect_timeout'] = 3;
         }
 
+        if (!isset($options['capacity'])) {
+            $options['capacity'] = 1000;
+        }
+
+        $this->_eventProcessor = new \LaunchDarkly\EventProcessor($apiKey, $options);
+
         $this->_client = $this->_make_client($options);
     }
 
@@ -54,13 +62,51 @@ public function __construct($apiKey, $options = []) {
     public function getFlag($key, $user, $default = false) {
         try {
             $flag = $this->_getFlag($key, $user, $default);
-            return is_null($flag) ? $default : $flag;
+
+            if (is_null($flag)) {
+                $this->_sendFlagRequestEvent($key, $user, $default);
+                return $default;
+            }
+            else {
+                $this->_sendFlagRequestEvent($key, $user, $flag);                
+                return $flag;
+            }
         } catch (Exception $e) {
             error_log("LaunchDarkly caught $e");
+            $this->_sendFlagRequestEvent($key, $user, $default);            
             return $default;
         }
     }
 
+    /**
+     * Tracks that a user performed an event.
+     *
+     * @param string $eventName The name of the event
+     * @param LDUser $user The user that performed the event
+     *
+     */
+    public function sendEvent($eventName, $user, $data) {
+        $event = array();
+        $event['user'] = $user->toJSON();
+        $event['kind'] = "custom";
+        $event['creationDate'] = round(microtime(1) * 1000);
+        $event['key'] = $eventName;
+        if (isset($data)) {
+            $event['data'] = $data;
+        }
+        $this->_eventProcessor->enqueue($event);
+    }
+
+    protected function _sendFlagRequestEvent($key, $user, $value) {
+        $event = array();
+        $event['user'] = $user->toJSON();
+        $event['value'] = $value;
+        $event['kind'] = "feature";
+        $event['creationDate'] = round(microtime(1) * 1000);
+        $event['key'] = $key;
+        $this->_eventProcessor->enqueue($event); 
+    }
+
     protected function _getFlag($key, $user, $default) {
         try {
             $response = $this->_client->get("/api/eval/features/$key");
diff --git a/src/LaunchDarkly/LDUser.php b/src/LaunchDarkly/LDUser.php
index c014a334b..85a3cd379 100644
--- a/src/LaunchDarkly/LDUser.php
+++ b/src/LaunchDarkly/LDUser.php
@@ -47,4 +47,22 @@ public function getKey() {
     public function getSecondary() {
         return $this->_secondary;
     }
+
+    public function toJSON() {
+        $json = ["key" => $this->_key];
+
+        if (isset($this->_secondary)) {
+            $json['secondary'] = $this->_secondary;
+        }
+        if (isset($this->ip)) {
+            $json['ip'] = $this->ip;
+        }
+        if (isset($this->country)) {
+            $json['country'] = $this->country;
+        }
+        if (isset($this->custom)) {
+            $json['custom'] = $this->custom;
+        }
+        return $json;
+    }
 }