diff --git a/.gitignore b/.gitignore
index 485dee6..45b1244 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 .idea
+/vendor
\ No newline at end of file
diff --git a/README.md b/README.md
index 97d8d02..9d6993b 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ Here's a small example.
 ```php
 try {
     $jobd = new jobd\MasterClient();
-} catch (jobd\Exception $e) {
+} catch (\jobd\exceptions\JobdException $e) {
     die("Failed to connect.\n");
 }
 
@@ -29,7 +29,7 @@ try {
     
     // get status from master
     $status = $jobd->status()->getData();
-} catch (jobd\Exception $e) {
+} catch (\jobd\exceptions\JobdException $e) {
     die('jobd error: '.$e->getMessage()."\n");
 }
 
diff --git a/composer.json b/composer.json
index f2dde7c..0fbb9f7 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
   "name": "ch1p/jobd-client",
-  "version": "1.5.2",
+  "version": "1.6.0",
   "license": "BSD-2-Clause",
   "keywords": ["queue", "job", "jobd"],
   "repositories": [
@@ -11,7 +11,9 @@
   ],
   "autoload": {
     "psr-4": {
-      "jobd\\": "src/"
+      "jobd\\": "src/",
+      "jobd\\messages\\": "src/messages",
+      "jobd\\exceptions\\": "src/exceptions"
     }
   },
   "require": {
diff --git a/composer.lock b/composer.lock
new file mode 100644
index 0000000..768bcea
--- /dev/null
+++ b/composer.lock
@@ -0,0 +1,22 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "3ea2178ffa7d2dde56d1c2ac872d7c34",
+    "packages": [],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": [],
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": {
+        "php": ">=7.0",
+        "ext-json": "*",
+        "ext-sockets": "*"
+    },
+    "platform-dev": [],
+    "plugin-api-version": "2.3.0"
+}
diff --git a/src/Client.php b/src/Client.php
index b4628ca..b66b6e7 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -2,8 +2,14 @@
 
 namespace jobd;
 
+use jobd\exceptions\JobdException;
+use jobd\messages\Message;
+use jobd\messages\PingMessage;
+use jobd\messages\PongMessage;
+use jobd\messages\RequestMessage;
+use jobd\messages\ResponseMessage;
 
-class Client {
+abstract class Client {
 
     const WORKER_PORT = 7080;
     const MASTER_PORT = 7081;
@@ -23,7 +29,7 @@ class Client {
      * @param int $port
      * @param string $host
      * @param string $password
-     * @throws Exception
+     * @throws JobdException
      */
     public function __construct(int $port, string $host = '127.0.0.1', string $password = '')
     {
@@ -32,12 +38,12 @@ class Client {
         $this->password = $password;
 
         if (($socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) === false)
-            throw new Exception("socket_create() failed: ".$this->getSocketError());
+            throw new JobdException("socket_create() failed: ".$this->getSocketError());
 
         $this->sock = $socket;
 
         if ((socket_connect($socket, $host, $port)) === false)
-            throw new Exception("socket_connect() failed: ".$this->getSocketError());
+            throw new JobdException("socket_connect() failed: ".$this->getSocketError());
 
         $this->lastOutgoingRequestNo = mt_rand(1 /* 0 is reserved */, self::REQUEST_NO_LIMIT);
     }
@@ -53,7 +59,7 @@ class Client {
     /**
      * @param string[] $targets
      * @return ResponseMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function pause(array $targets = []): ResponseMessage
     {
@@ -69,7 +75,7 @@ class Client {
     /**
      * @param string[] $targets
      * @return ResponseMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function continue(array $targets = []): ResponseMessage
     {
@@ -84,7 +90,7 @@ class Client {
 
     /**
      * @return PongMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function ping(): PongMessage
     {
@@ -113,7 +119,7 @@ class Client {
 
     /**
      * @param Message $message
-     * @throws Exception
+     * @throws JobdException
      */
     public function send(Message $message)
     {
@@ -123,7 +129,7 @@ class Client {
         while ($remained > 0) {
             $result = socket_write($this->sock, $data);
             if ($result === false)
-                throw new Exception(__METHOD__ . ": socket_write() failed: ".$this->getSocketError());
+                throw new JobdException(__METHOD__ . ": socket_write() failed: ".$this->getSocketError());
 
             $remained -= $result;
             if ($remained > 0)
@@ -134,7 +140,7 @@ class Client {
     /**
      * @param int $request_no
      * @return RequestMessage|ResponseMessage|PingMessage|PongMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function recv(int $request_no = -1)
     {
@@ -145,7 +151,7 @@ class Client {
         while (true) {
             $result = socket_recv($this->sock, $recv_buf, 1024, 0);
             if ($result === false)
-                throw new Exception(__METHOD__ . ": socket_recv() failed: " . $this->getSocketError());
+                throw new JobdException(__METHOD__ . ": socket_recv() failed: " . $this->getSocketError());
 
             // peer disconnected
             if ($result === 0)
@@ -172,7 +178,7 @@ class Client {
         } while ($eot_pos !== false && $offset < $buflen-1);
 
         if (empty($messages))
-            throw new Exception("Malformed response: no messages found. Response: {$buf}");
+            throw new JobdException("Malformed response: no messages found. Response: {$buf}");
 
         if (count($messages) > 1)
             trigger_error(__METHOD__.": received more than one message");
@@ -196,7 +202,7 @@ class Client {
             );
 
             if (empty($messages))
-                throw new Exception("Malformed response: response for {$request_no} not found.");
+                throw new JobdException("Malformed response: response for {$request_no} not found.");
 
 
             if (count($messages) == 2) {
@@ -220,7 +226,7 @@ class Client {
 
         if ($response instanceof ResponseMessage) {
             if ($error = $response->getError())
-                throw new Exception($response->getError());
+                throw new JobdException($response->getError());
         }
 
         return $response;
@@ -242,13 +248,13 @@ class Client {
     /**
      * @param string $raw_string
      * @return RequestMessage|ResponseMessage|PingMessage|PongMessage
-     * @throws Exception
+     * @throws JobdException
      */
     protected static function parseMessage(string $raw_string)
     {
         $raw = json_decode($raw_string, true);
         if (!is_array($raw) || count($raw) < 1)
-            throw new Exception("Malformed message: {$raw_string}");
+            throw new JobdException("Malformed message: {$raw_string}");
 
         list($type) = $raw;
 
@@ -263,8 +269,8 @@ class Client {
                         ['password', 's',     false],
                         ['data',     'a',     false]
                     ]);
-                } catch (Exception $e) {
-                    throw new Exception("Malformed REQUEST message: {$e->getMessage()}");
+                } catch (JobdException $e) {
+                    throw new JobdException("Malformed REQUEST message: {$e->getMessage()}");
                 }
 
                 $message = new RequestMessage($data['type'], $data['data'] ?? null);
@@ -283,8 +289,8 @@ class Client {
                         ['data',  'aifs',  false],
                         ['error', 's',     false],
                     ]);
-                } catch (Exception $e) {
-                    throw new Exception("Malformed RESPONSE message: {$e->getMessage()}");
+                } catch (JobdException $e) {
+                    throw new JobdException("Malformed RESPONSE message: {$e->getMessage()}");
                 }
 
                 return new ResponseMessage($data['no'], $data['error'] ?? null, $data['data'] ?? null);
@@ -296,25 +302,25 @@ class Client {
                 return new PongMessage();
 
             default:
-                throw new Exception("Malformed message: unexpected type {$type}");
+                throw new JobdException("Malformed message: unexpected type {$type}");
         }
     }
 
     /**
      * @param mixed $data
      * @param array $schema
-     * @throws Exception
+     * @throws JobdException
      */
     protected static function validateData($data, array $schema)
     {
         if (!$data || !is_array($data))
-            throw new Exception('data must be array');
+            throw new JobdException('data must be array');
 
         foreach ($schema as $schema_item) {
             list ($key_name, $key_types, $key_required) = $schema_item;
             if (!isset($data[$key_name])) {
                 if ($key_required)
-                    throw new Exception("'{$key_name}' is missing");
+                    throw new JobdException("'{$key_name}' is missing");
 
                 continue;
             }
@@ -354,7 +360,7 @@ class Client {
             }
 
             if (!$passed)
-                throw new Exception("{$key_name}: required type is '{$key_types}'");
+                throw new JobdException("{$key_name}: required type is '{$key_types}'");
         }
     }
 
diff --git a/src/Exception.php b/src/Exception.php
deleted file mode 100644
index be64d4c..0000000
--- a/src/Exception.php
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-
-namespace jobd;
-
-class Exception extends \Exception {}
\ No newline at end of file
diff --git a/src/MasterClient.php b/src/MasterClient.php
index d85e454..2fed338 100644
--- a/src/MasterClient.php
+++ b/src/MasterClient.php
@@ -2,6 +2,10 @@
 
 namespace jobd;
 
+use jobd\exceptions\JobdException;
+use jobd\messages\RequestMessage;
+use jobd\messages\ResponseMessage;
+
 class MasterClient extends Client {
 
     public function __construct(int $port = Client::MASTER_PORT, ...$args)
@@ -12,7 +16,7 @@ class MasterClient extends Client {
     /**
      * @param array $targets
      * @return ResponseMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function poke(array $targets): ResponseMessage
     {
@@ -24,7 +28,7 @@ class MasterClient extends Client {
     /**
      * @param bool $poll_workers
      * @return ResponseMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function status(bool $poll_workers = false): ResponseMessage
     {
@@ -36,7 +40,7 @@ class MasterClient extends Client {
     /**
      * @param array[] $jobs
      * @return ResponseMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function runManual(array $jobs): ResponseMessage
     {
@@ -45,4 +49,33 @@ class MasterClient extends Client {
         );
     }
 
+    /**
+     * @param int $job_id
+     * @param int $signal
+     * @param string $target
+     * @return ResponseMessage
+     * @throws JobdException
+     */
+    public function sendSignal(int $job_id, int $signal, string $target): ResponseMessage
+    {
+        return $this->sendSignals([
+            [
+                'id' => $job_id,
+                'signal' => $signal,
+                'target' => $target
+            ]
+        ]);
+    }
+
+    /**
+     * @param array $data
+     * @return ResponseMessage
+     * @throws JobdException
+     */
+    public function sendSignals(array $data): ResponseMessage {
+        return $this->recv(
+            $this->sendRequest(new RequestMessage('send-signal', ['jobs' => $data]))
+        );
+    }
+
 }
\ No newline at end of file
diff --git a/src/WorkerClient.php b/src/WorkerClient.php
index 2773de5..16f8963 100644
--- a/src/WorkerClient.php
+++ b/src/WorkerClient.php
@@ -2,6 +2,10 @@
 
 namespace jobd;
 
+use jobd\exceptions\JobdException;
+use jobd\messages\RequestMessage;
+use jobd\messages\ResponseMessage;
+
 class WorkerClient extends Client {
 
     public function __construct(int $port = Client::WORKER_PORT, ...$args)
@@ -48,11 +52,23 @@ class WorkerClient extends Client {
         );
     }
 
+    /**
+     * @param array[] $jobs
+     * @return ResponseMessage
+     * @throws JobdException
+     */
+    public function sendSignal(array $jobs): ResponseMessage
+    {
+        return $this->recv(
+            $this->sendRequest(new RequestMessage('send-signal', ['jobs' => $jobs]))
+        );
+    }
+
     /**
      * @param string $target
      * @param int $concurrency
      * @return ResponseMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function addTarget(string $target, int $concurrency): ResponseMessage
     {
@@ -67,7 +83,7 @@ class WorkerClient extends Client {
     /**
      * @param string $target
      * @return ResponseMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function removeTarget(string $target): ResponseMessage
     {
@@ -82,7 +98,7 @@ class WorkerClient extends Client {
      * @param string $target
      * @param int $concurrency
      * @return ResponseMessage
-     * @throws Exception
+     * @throws JobdException
      */
     public function setTargetConcurrency(string $target, int $concurrency): ResponseMessage
     {
diff --git a/src/exceptions/JobInterruptedException.php b/src/exceptions/JobInterruptedException.php
new file mode 100644
index 0000000..c645cc5
--- /dev/null
+++ b/src/exceptions/JobInterruptedException.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace jobd\exceptions;
+
+class JobInterruptedException extends \Exception {
+
+    public function __construct(int $code = 1, string $message = "") {
+        parent::__construct($message, $code);
+    }
+
+}
\ No newline at end of file
diff --git a/src/exceptions/JobdException.php b/src/exceptions/JobdException.php
new file mode 100644
index 0000000..59b218c
--- /dev/null
+++ b/src/exceptions/JobdException.php
@@ -0,0 +1,5 @@
+<?php
+
+namespace jobd\exceptions;
+
+class JobdException extends \Exception {}
\ No newline at end of file
diff --git a/src/Message.php b/src/messages/Message.php
similarity index 96%
rename from src/Message.php
rename to src/messages/Message.php
index d5df6ab..df7464e 100644
--- a/src/Message.php
+++ b/src/messages/Message.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace jobd;
+namespace jobd\messages;
 
 
 abstract class Message {
diff --git a/src/PingMessage.php b/src/messages/PingMessage.php
similarity index 89%
rename from src/PingMessage.php
rename to src/messages/PingMessage.php
index f3441c9..fa61379 100644
--- a/src/PingMessage.php
+++ b/src/messages/PingMessage.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace jobd;
+namespace jobd\messages;
 
 class PingMessage extends Message {
 
diff --git a/src/PongMessage.php b/src/messages/PongMessage.php
similarity index 89%
rename from src/PongMessage.php
rename to src/messages/PongMessage.php
index a0a38a0..00bb499 100644
--- a/src/PongMessage.php
+++ b/src/messages/PongMessage.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace jobd;
+namespace jobd\messages;
 
 class PongMessage extends Message {
 
diff --git a/src/RequestMessage.php b/src/messages/RequestMessage.php
similarity index 97%
rename from src/RequestMessage.php
rename to src/messages/RequestMessage.php
index a2e196d..12ab7ad 100644
--- a/src/RequestMessage.php
+++ b/src/messages/RequestMessage.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace jobd;
+namespace jobd\messages;
 
 class RequestMessage extends Message {
 
diff --git a/src/ResponseMessage.php b/src/messages/ResponseMessage.php
similarity index 97%
rename from src/ResponseMessage.php
rename to src/messages/ResponseMessage.php
index 1f91dd4..5101ed4 100644
--- a/src/ResponseMessage.php
+++ b/src/messages/ResponseMessage.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace jobd;
+namespace jobd\messages;
 
 class ResponseMessage extends Message {