diff --git a/deflect/MessageHeader.h b/deflect/MessageHeader.h
index c94f5a0..e6aab26 100644
--- a/deflect/MessageHeader.h
+++ b/deflect/MessageHeader.h
@@ -66,7 +66,8 @@ enum MessageType
     MESSAGE_TYPE_BIND_EVENTS_REPLY = 8,
     MESSAGE_TYPE_EVENT = 9,
     MESSAGE_TYPE_QUIT = 12,
-    MESSAGE_TYPE_SIZE_HINTS = 13
+    MESSAGE_TYPE_SIZE_HINTS = 13,
+    MESSAGE_TYPE_DATA = 14
 };
 
 #define MESSAGE_HEADER_URI_LENGTH 64
diff --git a/deflect/Server.cpp b/deflect/Server.cpp
index 8f9a463..f6d0b9f 100644
--- a/deflect/Server.cpp
+++ b/deflect/Server.cpp
@@ -138,6 +138,8 @@ void Server::incomingConnection( const qintptr socketHandle )
              this, &Server::registerToEvents );
     connect( worker, &ServerWorker::receivedSizeHints,
              this, &Server::receivedSizeHints );
+    connect( worker, &ServerWorker::receivedData,
+             this, &Server::receivedData );
     connect( this, &Server::_pixelStreamerClosed,
              worker, &ServerWorker::closeConnection );
     connect( this, &Server::_eventRegistrationReply,
diff --git a/deflect/Server.h b/deflect/Server.h
index ee83061..40590e5 100644
--- a/deflect/Server.h
+++ b/deflect/Server.h
@@ -83,6 +83,8 @@ class DEFLECT_API Server : public QTcpServer
 
     void receivedSizeHints( QString uri, deflect::SizeHints hints );
 
+    void receivedData( QString uri, QByteArray data );
+
 public slots:
     void onPixelStreamerClosed( QString uri );
     void onEventRegistrationReply( QString uri, bool success );
diff --git a/deflect/ServerWorker.cpp b/deflect/ServerWorker.cpp
index 2352bfe..e15acb9 100644
--- a/deflect/ServerWorker.cpp
+++ b/deflect/ServerWorker.cpp
@@ -242,6 +242,10 @@ void ServerWorker::_handleMessage( const MessageHeader& messageHeader,
         break;
     }
 
+    case MESSAGE_TYPE_DATA:
+        emit receivedData( _streamId, byteArray );
+        break;
+
     case MESSAGE_TYPE_BIND_EVENTS:
     case MESSAGE_TYPE_BIND_EVENTS_EX:
         if( _registeredToEvents )
diff --git a/deflect/ServerWorker.h b/deflect/ServerWorker.h
index d127219..7cc0b03 100644
--- a/deflect/ServerWorker.h
+++ b/deflect/ServerWorker.h
@@ -81,6 +81,8 @@ public slots:
 
     void receivedSizeHints( QString uri, deflect::SizeHints hints );
 
+    void receivedData( QString uri, QByteArray data );
+
     void connectionClosed();
 
     /** @internal */
diff --git a/deflect/Stream.cpp b/deflect/Stream.cpp
index 9496c6d..a3cf2e6 100644
--- a/deflect/Stream.cpp
+++ b/deflect/Stream.cpp
@@ -189,4 +189,9 @@ void Stream::sendSizeHints( const SizeHints& hints )
     _impl->sendSizeHints( hints );
 }
 
+bool Stream::sendData( const char* data, const size_t count )
+{
+    return _impl->send( QByteArray::fromRawData( data, count ));
+}
+
 }
diff --git a/deflect/Stream.h b/deflect/Stream.h
index a04c5c8..54c260a 100644
--- a/deflect/Stream.h
+++ b/deflect/Stream.h
@@ -259,6 +259,16 @@ class Stream
      */
     DEFLECT_API void sendSizeHints( const SizeHints& hints );
 
+    /**
+     * Send data to the Server.
+     *
+     * @param data the pointer to the data buffer.
+     * @param count the number of bytes to send.
+     * @return true if the data could be sent, false otherwise
+     * @version 1.3
+     */
+    DEFLECT_API bool sendData( const char* data, size_t count );
+
 private:
     Stream( const Stream& ) = delete;
     const Stream& operator = ( const Stream& ) = delete;
diff --git a/deflect/StreamPrivate.cpp b/deflect/StreamPrivate.cpp
index 706cc65..641c3d4 100644
--- a/deflect/StreamPrivate.cpp
+++ b/deflect/StreamPrivate.cpp
@@ -177,4 +177,10 @@ bool StreamPrivate::sendSizeHints( const SizeHints& hints )
     return socket.send( mh, message );
 }
 
+bool StreamPrivate::send( const QByteArray data )
+{
+    const MessageHeader mh( MESSAGE_TYPE_DATA, data.size(), id );
+    return socket.send( mh, data );
+}
+
 }
diff --git a/deflect/StreamPrivate.h b/deflect/StreamPrivate.h
index da776cc..c7ecc59 100644
--- a/deflect/StreamPrivate.h
+++ b/deflect/StreamPrivate.h
@@ -108,6 +108,9 @@ class StreamPrivate
     /** @sa Stream::sendSizeHints */
     bool sendSizeHints( const SizeHints& hints );
 
+    /** Send a user-defined block of data to the server. */
+    bool send( QByteArray data );
+
     /** The stream identifier. */
     const std::string id;
 
diff --git a/doc/Changelog.md b/doc/Changelog.md
index e6a9361..5870633 100644
--- a/doc/Changelog.md
+++ b/doc/Changelog.md
@@ -5,6 +5,9 @@ Changelog {#Changelog}
 
 ### 0.12.0 (git master)
 
+* [119](https://github.com/BlueBrain/Deflect/pull/119):
+  Added deflect::Stream::sendData() to allow sending user-defined information
+  to the deflect::Server.
 * [118](https://github.com/BlueBrain/Deflect/pull/118):
   New "pan" event for multi-finger pan gestures.
 * [117](https://github.com/BlueBrain/Deflect/pull/117):
diff --git a/tests/cpp/ServerTests.cpp b/tests/cpp/ServerTests.cpp
index 87eb624..6ac4ca6 100644
--- a/tests/cpp/ServerTests.cpp
+++ b/tests/cpp/ServerTests.cpp
@@ -174,3 +174,58 @@ BOOST_AUTO_TEST_CASE( testRegisterForEventReceivedByServer )
     }
     BOOST_CHECK( !"reachable" );
 }
+
+BOOST_AUTO_TEST_CASE( testDataReceivedByServer )
+{
+    QThread serverThread;
+    deflect::Server* server = new deflect::Server( 0 /* OS-chosen port */ );
+    server->moveToThread( &serverThread );
+    serverThread.connect( &serverThread, &QThread::finished,
+                          server, &deflect::Server::deleteLater );
+    serverThread.start();
+
+    QWaitCondition received;
+    QMutex mutex;
+
+    QString streamId;
+    std::string receivedData;
+    const auto sentData = std::string{ "Hello World!" };
+
+    bool receivedState = false;
+    server->connect( server, &deflect::Server::receivedData,
+             [&]( const QString id, QByteArray data )
+    {
+        streamId = id;
+        receivedData = QString( data ).toStdString();
+        mutex.lock();
+        receivedState = true;
+        received.wakeAll();
+        mutex.unlock();
+    });
+
+    {
+        deflect::Stream stream( testStreamId.toStdString(), "localhost",
+                                server->serverPort( ));
+        BOOST_REQUIRE( stream.isConnected( ));
+        stream.sendData( sentData.data(), sentData.size( ));
+    }
+
+    for( size_t i = 0; i < 20; ++i )
+    {
+        mutex.lock();
+        received.wait( &mutex, 100 /*ms*/ );
+        if( receivedState )
+        {
+            BOOST_CHECK_EQUAL( streamId.toStdString(),
+                               testStreamId.toStdString( ));
+            BOOST_CHECK_EQUAL( receivedData, sentData );
+
+            serverThread.quit();
+            serverThread.wait();
+            mutex.unlock();
+            return;
+        }
+        mutex.unlock();
+    }
+    BOOST_CHECK( !"reachable" );
+}