diff --git a/include/xeus-zmq/xclient_zmq.hpp b/include/xeus-zmq/xclient_zmq.hpp
index 1397c3b..186210b 100644
--- a/include/xeus-zmq/xclient_zmq.hpp
+++ b/include/xeus-zmq/xclient_zmq.hpp
@@ -34,31 +34,35 @@ namespace xeus
 
         explicit xclient_zmq(std::unique_ptr<xclient_zmq_impl> impl);
         ~xclient_zmq();
+        
+        void connect();
+        void start();
+        void stop_channels();
 
         void send_on_shell(xmessage msg);
         void send_on_control(xmessage msg);
 
-        std::optional<xmessage> check_shell_answer();
-        std::optional<xmessage> check_control_answer();
+        // APIs for receiving on a specified channel
+        std::optional<xmessage> receive_on_shell(bool bocking = true);
+        std::optional<xmessage> receive_on_control(bool blocking = true);
+
+        std::size_t iopub_queue_size() const;
+        std::optional<xpub_message> pop_iopub_message();
 
+        // APIs for receiving on all channels
         void register_shell_listener(const listener& l);
         void register_control_listener(const listener& l);
         void register_iopub_listener(const iopub_listener& l);
         void register_kernel_status_listener(const kernel_status_listener& l);
 
-        void notify_shell_listener(xmessage msg);
-        void notify_control_listener(xmessage msg);
-        void notify_iopub_listener(xpub_message msg);
-        void notify_kernel_dead(bool status);
-
-        std::size_t iopub_queue_size() const;
-        std::optional<xpub_message> pop_iopub_message();
-        void connect();
-        void stop_channels();
-        void start();
         void wait_for_message();
 
     private:
+
+        void notify_shell_listener(xmessage msg);
+        void notify_control_listener(xmessage msg);
+        void notify_iopub_listener(xpub_message msg);
+        
         std::unique_ptr<xclient_zmq_impl> p_client_impl;
     };
 
@@ -68,4 +72,4 @@ namespace xeus
                                               nl::json::error_handler_t eh = nl::json::error_handler_t::strict);
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/client/xclient_zmq.cpp b/src/client/xclient_zmq.cpp
index cedc9c2..365e395 100644
--- a/src/client/xclient_zmq.cpp
+++ b/src/client/xclient_zmq.cpp
@@ -22,6 +22,20 @@ namespace xeus
     // types are used in unique_ptr in the header
     xclient_zmq::~xclient_zmq() = default;
 
+    void xclient_zmq::connect()
+    {
+        p_client_impl->connect();
+    }
+
+    void xclient_zmq::start()
+    {
+        p_client_impl->start();
+    }
+
+    void xclient_zmq::stop_channels()
+    {
+        p_client_impl->stop_channels();
+    }
 
     void xclient_zmq::send_on_shell(xmessage msg)
     {
@@ -33,14 +47,24 @@ namespace xeus
         p_client_impl->send_on_control(std::move(msg));
     }
 
-    std::optional<xmessage> xclient_zmq::check_shell_answer()
+    std::optional<xmessage> xclient_zmq::receive_on_shell(bool blocking)
+    {
+        return p_client_impl->receive_on_shell(blocking);
+    }
+
+    std::optional<xmessage> xclient_zmq::receive_on_control(bool blocking)
+    {
+        return p_client_impl->receive_on_control(blocking);
+    }
+
+    std::size_t xclient_zmq::iopub_queue_size() const
     {
-        return p_client_impl->receive_on_shell(0);
+        return p_client_impl->iopub_queue_size();
     }
 
-    std::optional<xmessage> xclient_zmq::check_control_answer()
+    std::optional<xpub_message> xclient_zmq::pop_iopub_message()
     {
-        return p_client_impl->receive_on_control(0);
+        return p_client_impl->pop_iopub_message();
     }
 
     void xclient_zmq::register_shell_listener(const listener& l)
@@ -63,6 +87,11 @@ namespace xeus
         p_client_impl->register_kernel_status_listener(l);
     }
 
+    void xclient_zmq::wait_for_message()
+    {
+        p_client_impl->wait_for_message();
+    }
+
     void xclient_zmq::notify_shell_listener(xmessage msg)
     {
         p_client_impl->notify_shell_listener(std::move(msg));
@@ -77,42 +106,7 @@ namespace xeus
     {
         p_client_impl->notify_iopub_listener(std::move(msg));
     }
-
-    void xclient_zmq::notify_kernel_dead(bool status)
-    {
-        p_client_impl->notify_kernel_dead(status);
-    }
-
-    std::size_t xclient_zmq::iopub_queue_size() const
-    {
-        return p_client_impl->iopub_queue_size();
-    }
-
-    std::optional<xpub_message> xclient_zmq::pop_iopub_message()
-    {
-        return p_client_impl->pop_iopub_message();
-    }
-
-    void xclient_zmq::connect()
-    {
-        p_client_impl->connect();
-    }
-
-    void xclient_zmq::stop_channels()
-    {
-        p_client_impl->stop_channels();
-    }
-
-    void xclient_zmq::start()
-    {
-        p_client_impl->start();
-    }
-
-    void xclient_zmq::wait_for_message()
-    {
-        p_client_impl->wait_for_message();
-    }
-
+    
     std::unique_ptr<xclient_zmq> make_xclient_zmq(xcontext& context,
                                                 const xconfiguration& config,
                                                 nl::json::error_handler_t eh)
diff --git a/src/client/xclient_zmq_impl.cpp b/src/client/xclient_zmq_impl.cpp
index f4be177..9190762 100644
--- a/src/client/xclient_zmq_impl.cpp
+++ b/src/client/xclient_zmq_impl.cpp
@@ -50,26 +50,30 @@ namespace xeus
         m_control_client.send_message(wire_msg);
     }
 
-    std::optional<xmessage> xclient_zmq_impl::receive_on_shell(long timeout)
+    std::optional<xmessage> xclient_zmq_impl::receive_on_shell(bool blocking)
     {
-        std::optional<zmq::multipart_t> wire_msg = m_shell_client.receive_message(timeout);
+        std::optional<zmq::multipart_t> wire_msg = m_shell_client.receive_message(blocking);
 
         if (wire_msg.has_value())
         {
             return deserialize(wire_msg.value());
-        } else {
+        }
+        else
+        {
             return std::nullopt;
         }
     }
 
-    std::optional<xmessage> xclient_zmq_impl::receive_on_control(long timeout)
+    std::optional<xmessage> xclient_zmq_impl::receive_on_control(bool blocking)
     {
-        std::optional<zmq::multipart_t> wire_msg = m_control_client.receive_message(timeout);
+        std::optional<zmq::multipart_t> wire_msg = m_control_client.receive_message(blocking);
 
         if (wire_msg.has_value())
         {
             return deserialize(wire_msg.value());
-        } else {
+        }
+        else
+        {
             return std::nullopt;
         }
     }
diff --git a/src/client/xclient_zmq_impl.hpp b/src/client/xclient_zmq_impl.hpp
index f733865..11fa286 100644
--- a/src/client/xclient_zmq_impl.hpp
+++ b/src/client/xclient_zmq_impl.hpp
@@ -51,12 +51,12 @@ namespace xeus
 
         // shell channel
         void send_on_shell(xmessage msg);
-        std::optional<xmessage> receive_on_shell(long timeout);
+        std::optional<xmessage> receive_on_shell(bool blocking);
         void register_shell_listener(const listener& l);
 
         // control channel
         void send_on_control(xmessage msg);
-        std::optional<xmessage> receive_on_control(long timeout);
+        std::optional<xmessage> receive_on_control(bool blocking);
         void register_control_listener(const listener& l);
 
         // iopub channel
@@ -83,6 +83,7 @@ namespace xeus
         xpub_message deserialize_iopub(zmq::multipart_t& wire_msg) const;
 
     private:
+
         void start_iopub_thread();
         void start_heartbeat_thread();
         void poll(long timeout);
diff --git a/src/client/xdealer_channel.cpp b/src/client/xdealer_channel.cpp
index 57dc892..85629c8 100644
--- a/src/client/xdealer_channel.cpp
+++ b/src/client/xdealer_channel.cpp
@@ -35,12 +35,12 @@ namespace xeus
         message.send(m_socket);
     }
 
-    std::optional<zmq::multipart_t> xdealer_channel::receive_message(long timeout)
+    std::optional<zmq::multipart_t> xdealer_channel::receive_message(bool blocking)
     {
         zmq::multipart_t wire_msg;
         zmq::recv_flags flags = zmq::recv_flags::none;
 
-        if (timeout == 0)
+        if (!blocking)
         {
             flags = zmq::recv_flags::dontwait;
         }
@@ -48,7 +48,9 @@ namespace xeus
         if (wire_msg.recv(m_socket, static_cast<int>(flags)))
         {
             return wire_msg;
-        } else {
+        }
+        else
+        {
             return std::nullopt;
         }
     }
@@ -57,4 +59,4 @@ namespace xeus
     {
         return m_socket;
     }
-}
\ No newline at end of file
+}
diff --git a/src/client/xdealer_channel.hpp b/src/client/xdealer_channel.hpp
index 871f2e8..917e2bf 100644
--- a/src/client/xdealer_channel.hpp
+++ b/src/client/xdealer_channel.hpp
@@ -28,15 +28,15 @@ namespace xeus
         ~xdealer_channel();
 
         void send_message(zmq::multipart_t& message);
-        std::optional<zmq::multipart_t> receive_message(long timeout);
+        std::optional<zmq::multipart_t> receive_message(bool blocking);
 
         zmq::socket_t& get_socket();
 
     private:
-        zmq::socket_t m_socket;
 
+        zmq::socket_t m_socket;
         std::string m_dealer_end_point;
     };
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/test/client_ipc.cpp b/test/client_ipc.cpp
index 4f74dfb..fbf8bf9 100644
--- a/test/client_ipc.cpp
+++ b/test/client_ipc.cpp
@@ -52,7 +52,7 @@ int main(int, char**)
 
     ipc_client.send_on_shell(std::move(msg));
 
-    auto response = ipc_client.check_shell_answer();
+    auto response = ipc_client.receive_on_shell(false);
     if (response.has_value())
     {
         std::cout << response->content().dump(4) << std::endl;
diff --git a/test/xipc_client.cpp b/test/xipc_client.cpp
index 6521a9a..f6f5961 100644
--- a/test/xipc_client.cpp
+++ b/test/xipc_client.cpp
@@ -21,8 +21,8 @@ namespace xeus
         p_client->send_on_shell(std::move(msg));
     }
 
-    std::optional<xmessage> xipc_client::check_shell_answer()
+    std::optional<xmessage> xipc_client::receive_on_shell(bool blocking)
     {
-        return p_client->check_shell_answer();
+        return p_client->receive_on_shell(blocking);
     }
-}
\ No newline at end of file
+}
diff --git a/test/xipc_client.hpp b/test/xipc_client.hpp
index 62779f0..e814e4b 100644
--- a/test/xipc_client.hpp
+++ b/test/xipc_client.hpp
@@ -21,7 +21,7 @@ namespace xeus
         xipc_client(xcontext& context, const xconfiguration& config);
 
         void send_on_shell(xmessage msg);
-        std::optional<xmessage> check_shell_answer();
+        std::optional<xmessage> receive_on_shell(bool blocking = true);
 
     private:
         client_ptr p_client;