diff --git a/jerry-core/debugger/debugger-ws.c b/jerry-core/debugger/debugger-ws.c
index 8edb391a43..a19f4e80bc 100644
--- a/jerry-core/debugger/debugger-ws.c
+++ b/jerry-core/debugger/debugger-ws.c
@@ -46,17 +46,38 @@
  */
 #define JERRY_DEBUGGER_WEBSOCKET_LENGTH_MASK 0x7fu
 
+/**
+ * Size of websocket header size.
+ */
+#define JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE 2
+
 /**
  * Payload mask size in bytes of a websocket package.
  */
 #define JERRY_DEBUGGER_WEBSOCKET_MASK_SIZE 4
 
 /**
- *
+ * Maximum message size with 1 byte size field.
+ */
+#define JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX 125
+
+/**
+ * Waiting for data from the client.
  */
 #define JERRY_DEBUGGER_RECEIVE_DATA_MODE \
   (JERRY_DEBUGGER_BREAKPOINT_MODE | JERRY_DEBUGGER_CLIENT_SOURCE_MODE)
 
+/**
+ * WebSocket opcode types.
+ */
+typedef enum
+{
+  JERRY_DEBUGGER_WEBSOCKET_TEXT_FRAME = 1, /**< text frame */
+  JERRY_DEBUGGER_WEBSOCKET_BINARY_FRAME = 2, /**< binary frame */
+  JERRY_DEBUGGER_WEBSOCKET_CLOSE_CONNECTION = 8, /**< close connection */
+  JERRY_DEBUGGER_WEBSOCKET_PING = 9, /**< ping (keep alive) frame */
+  JERRY_DEBUGGER_WEBSOCKET_PONG = 10, /**< reply to ping frame */
+} jerry_websocket_opcode_type_t;
 
 /**
  * Header for incoming packets.
@@ -321,6 +342,25 @@ jerry_debugger_accept_connection (void)
   struct sockaddr_in addr;
   socklen_t sin_size = sizeof (struct sockaddr_in);
 
+  uint8_t *payload_p = JERRY_CONTEXT (debugger_send_buffer) + JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE;
+  JERRY_CONTEXT (debugger_send_buffer_payload_p) = payload_p;
+
+  uint8_t max_send_size = (JERRY_DEBUGGER_MAX_BUFFER_SIZE - JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE);
+  if (max_send_size > JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX)
+  {
+    max_send_size = JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX;
+  }
+  JERRY_CONTEXT (debugger_max_send_size) = max_send_size;
+
+  uint8_t receive_header_size = (JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE + JERRY_DEBUGGER_WEBSOCKET_MASK_SIZE);
+  uint8_t max_receive_size = (uint8_t) (JERRY_DEBUGGER_MAX_BUFFER_SIZE - receive_header_size);
+
+  if (max_receive_size > JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX)
+  {
+    max_receive_size = JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX;
+  }
+  JERRY_CONTEXT (debugger_max_receive_size) = max_receive_size;
+
   addr.sin_family = AF_INET;
   addr.sin_port = htons (JERRY_CONTEXT (debugger_port));
   addr.sin_addr.s_addr = INADDR_ANY;
@@ -384,7 +424,7 @@ jerry_debugger_accept_connection (void)
     return false;
   }
 
-  if (!jerry_debugger_send_configuration (JERRY_DEBUGGER_MAX_RECEIVE_SIZE))
+  if (!jerry_debugger_send_configuration (max_receive_size))
   {
     return false;
   }
@@ -430,14 +470,14 @@ jerry_debugger_close_connection (void)
 bool
 jerry_debugger_send (size_t data_size) /**< data size */
 {
-  jerry_debugger_send_type_t *message_p = (jerry_debugger_send_type_t *) JERRY_CONTEXT (debugger_send_buffer);
-  message_p->header.ws_opcode = JERRY_DEBUGGER_WEBSOCKET_FIN_BIT | JERRY_DEBUGGER_WEBSOCKET_BINARY_FRAME;
-  message_p->header.size = (uint8_t) (data_size - sizeof (jerry_debugger_send_header_t));
-  return jerry_debugger_send_tcp (JERRY_CONTEXT (debugger_send_buffer), data_size);
-} /* jerry_debugger_send */
+  JERRY_ASSERT (data_size <= JERRY_CONTEXT (debugger_max_send_size));
 
-JERRY_STATIC_ASSERT (JERRY_DEBUGGER_MAX_RECEIVE_SIZE < 126,
-                     maximum_debug_message_receive_size_must_be_smaller_than_126);
+  uint8_t *header_p = JERRY_CONTEXT (debugger_send_buffer);
+  header_p[0] = JERRY_DEBUGGER_WEBSOCKET_FIN_BIT | JERRY_DEBUGGER_WEBSOCKET_BINARY_FRAME;
+  header_p[1] = (uint8_t) data_size;
+
+  return jerry_debugger_send_tcp (header_p, data_size + JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE);
+} /* jerry_debugger_send */
 
 /**
  * Receive message from the client.
@@ -453,6 +493,7 @@ bool
 jerry_debugger_receive (jerry_debugger_uint8_data_t **message_data_p) /**< [out] data received from client */
 {
   JERRY_ASSERT (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED);
+  JERRY_ASSERT (JERRY_CONTEXT (debugger_max_receive_size) <= JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX);
 
   JERRY_ASSERT (message_data_p != NULL ? !!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_RECEIVE_DATA_MODE)
                                        : !(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_RECEIVE_DATA_MODE));
@@ -497,7 +538,7 @@ jerry_debugger_receive (jerry_debugger_uint8_data_t **message_data_p) /**< [out]
     }
 
     if ((recv_buffer_p[0] & ~JERRY_DEBUGGER_WEBSOCKET_OPCODE_MASK) != JERRY_DEBUGGER_WEBSOCKET_FIN_BIT
-        || (recv_buffer_p[1] & JERRY_DEBUGGER_WEBSOCKET_LENGTH_MASK) > JERRY_DEBUGGER_MAX_RECEIVE_SIZE
+        || (recv_buffer_p[1] & JERRY_DEBUGGER_WEBSOCKET_LENGTH_MASK) > JERRY_CONTEXT (debugger_max_receive_size)
         || !(recv_buffer_p[1] & JERRY_DEBUGGER_WEBSOCKET_MASK_BIT))
     {
       jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Unsupported Websocket message.\n");
diff --git a/jerry-core/debugger/debugger-ws.h b/jerry-core/debugger/debugger-ws.h
index 5d56743f20..3a7c97c807 100644
--- a/jerry-core/debugger/debugger-ws.h
+++ b/jerry-core/debugger/debugger-ws.h
@@ -27,37 +27,6 @@
  */
 #define JERRY_DEBUGGER_MAX_BUFFER_SIZE 128
 
-/**
- * Maximum number of bytes that can be sent in a single message.
- */
-#define JERRY_DEBUGGER_MAX_SEND_SIZE (JERRY_DEBUGGER_MAX_BUFFER_SIZE - 1)
-
-/**
- * Maximum number of bytes that can be received in a single message.
- */
-#define JERRY_DEBUGGER_MAX_RECEIVE_SIZE (JERRY_DEBUGGER_MAX_BUFFER_SIZE - 6)
-
-/**
- * WebSocket opcode types.
- */
-typedef enum
-{
-  JERRY_DEBUGGER_WEBSOCKET_TEXT_FRAME = 1, /**< text frame */
-  JERRY_DEBUGGER_WEBSOCKET_BINARY_FRAME = 2, /**< binary frame */
-  JERRY_DEBUGGER_WEBSOCKET_CLOSE_CONNECTION = 8, /**< close connection */
-  JERRY_DEBUGGER_WEBSOCKET_PING = 9, /**< ping (keep alive) frame */
-  JERRY_DEBUGGER_WEBSOCKET_PONG = 10, /**< reply to ping frame */
-} jerry_websocket_opcode_type_t;
-
-/**
- * Header for outgoing packets.
- */
-typedef struct
-{
-  uint8_t ws_opcode; /**< Websocket opcode */
-  uint8_t size; /**< size of the message */
-} jerry_debugger_send_header_t;
-
 /**
  * Incoming message: next message of string data.
  */
diff --git a/jerry-core/debugger/debugger.c b/jerry-core/debugger/debugger.c
index 5df7e42d4b..0d4d45ebd4 100644
--- a/jerry-core/debugger/debugger.c
+++ b/jerry-core/debugger/debugger.c
@@ -37,7 +37,7 @@ JERRY_STATIC_ASSERT (JERRY_DEBUGGER_MESSAGES_OUT_MAX_COUNT == 27
  * Type cast the debugger send buffer into a specific type.
  */
 #define JERRY_DEBUGGER_SEND_BUFFER_AS(type, name_p) \
-  type *name_p = (type *) (&JERRY_CONTEXT (debugger_send_buffer))
+  type *name_p = (type *) (JERRY_CONTEXT (debugger_send_buffer_payload_p))
 
 /**
  * Type cast the debugger receive buffer into a specific type.
@@ -92,7 +92,9 @@ jerry_debugger_send_backtrace (uint8_t *recv_buffer_p) /**< pointer to the recei
 
   vm_frame_ctx_t *frame_ctx_p = JERRY_CONTEXT (vm_top_context_p);
 
-  uint32_t current_frame = 0;
+  size_t current_frame = 0;
+  const size_t max_frame_count = JERRY_DEBUGGER_SEND_MAX (jerry_debugger_frame_t);
+  const size_t max_message_size = JERRY_DEBUGGER_SEND_SIZE (max_frame_count, jerry_debugger_frame_t);
 
   while (frame_ctx_p != NULL && max_depth > 0)
   {
@@ -102,9 +104,9 @@ jerry_debugger_send_backtrace (uint8_t *recv_buffer_p) /**< pointer to the recei
       continue;
     }
 
-    if (current_frame >= JERRY_DEBUGGER_SEND_MAX (jerry_debugger_frame_t))
+    if (current_frame >= max_frame_count)
     {
-      if (!jerry_debugger_send (sizeof (jerry_debugger_send_backtrace_t)))
+      if (!jerry_debugger_send (max_message_size))
       {
         return;
       }
@@ -533,7 +535,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       memcpy (&eval_size, eval_first_p->eval_size, sizeof (uint32_t));
       bool is_eval = (recv_buffer_p[0] == JERRY_DEBUGGER_EVAL);
 
-      if (eval_size <= JERRY_DEBUGGER_MAX_RECEIVE_SIZE - sizeof (jerry_debugger_receive_eval_first_t))
+      if (eval_size <= JERRY_CONTEXT (debugger_max_receive_size) - sizeof (jerry_debugger_receive_eval_first_t))
       {
         if (eval_size != message_size - sizeof (jerry_debugger_receive_eval_first_t))
         {
@@ -590,8 +592,10 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       uint32_t client_source_size;
       memcpy (&client_source_size, client_source_first_p->code_size, sizeof (uint32_t));
 
-      if (client_source_size <= JERRY_DEBUGGER_MAX_RECEIVE_SIZE - sizeof (jerry_debugger_receive_client_source_first_t)
-          && client_source_size != message_size - sizeof (jerry_debugger_receive_client_source_first_t))
+      uint32_t header_size = sizeof (jerry_debugger_receive_client_source_first_t);
+
+      if (client_source_size <= JERRY_CONTEXT (debugger_max_receive_size) - header_size
+          && client_source_size != message_size - header_size)
       {
         jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Invalid message size\n");
         jerry_debugger_close_connection ();
@@ -796,37 +800,42 @@ jerry_debugger_send_string (uint8_t message_type, /**< message type */
 {
   JERRY_ASSERT (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED);
 
-  const size_t max_fragment_len = JERRY_DEBUGGER_SEND_MAX (uint8_t);
+  const size_t max_byte_count = JERRY_DEBUGGER_SEND_MAX (uint8_t);
+  const size_t max_message_size = JERRY_DEBUGGER_SEND_SIZE (max_byte_count, uint8_t);
 
   JERRY_DEBUGGER_SEND_BUFFER_AS (jerry_debugger_send_string_t, message_string_p);
 
   message_string_p->type = message_type;
 
-  while (string_length > max_fragment_len)
+  if (sub_type != JERRY_DEBUGGER_NO_SUBTYPE)
   {
-    memcpy (message_string_p->string, string_p, max_fragment_len);
+    string_length += 1;
+  }
 
-    if (!jerry_debugger_send (sizeof (jerry_debugger_send_string_t)))
+  while (string_length > max_byte_count)
+  {
+    memcpy (message_string_p->string, string_p, max_byte_count);
+
+    if (!jerry_debugger_send (max_message_size))
     {
       return false;
     }
 
-    string_length -= max_fragment_len;
-    string_p += max_fragment_len;
-  }
-
-  if (sub_type != JERRY_DEBUGGER_NO_SUBTYPE)
-  {
-    string_length += 1;
+    string_length -= max_byte_count;
+    string_p += max_byte_count;
   }
 
   message_string_p->type = (uint8_t) (message_type + 1);
 
-  memcpy (message_string_p->string, string_p, string_length);
   if (sub_type != JERRY_DEBUGGER_NO_SUBTYPE)
   {
+    memcpy (message_string_p->string, string_p, string_length - 1);
     message_string_p->string[string_length - 1] = sub_type;
   }
+  else
+  {
+    memcpy (message_string_p->string, string_p, string_length);
+  }
 
   return jerry_debugger_send (sizeof (jerry_debugger_send_type_t) + string_length);
 } /* jerry_debugger_send_string */
diff --git a/jerry-core/debugger/debugger.h b/jerry-core/debugger/debugger.h
index ff7dba2047..8e4ac0964e 100644
--- a/jerry-core/debugger/debugger.h
+++ b/jerry-core/debugger/debugger.h
@@ -53,10 +53,16 @@
 
 /**
  * Calculate the maximum number of items for a given type
- * which can be transmitted by one message.
+ * which can be transmitted in one message.
  */
 #define JERRY_DEBUGGER_SEND_MAX(type) \
- ((JERRY_DEBUGGER_MAX_SEND_SIZE - sizeof (jerry_debugger_send_header_t) - 1) / sizeof (type))
+  ((size_t) ((JERRY_CONTEXT (debugger_max_send_size) - sizeof (jerry_debugger_send_type_t)) / sizeof (type)))
+
+/**
+ * Calculate the size of a message when a count number of items transmitted.
+ */
+#define JERRY_DEBUGGER_SEND_SIZE(count, type) \
+  ((size_t) ((count * sizeof (type)) + sizeof (jerry_debugger_send_type_t)))
 
 /**
  * Debugger operation modes:
@@ -226,7 +232,6 @@ typedef struct
  */
 typedef struct
 {
-  jerry_debugger_send_header_t header; /**< message header */
   uint8_t type; /**< type of the message */
   uint8_t max_message_size; /**< maximum incoming message size */
   uint8_t cpointer_size; /**< size of compressed pointers */
@@ -239,7 +244,6 @@ typedef struct
  */
 typedef struct
 {
-  jerry_debugger_send_header_t header; /**< message header */
   uint8_t type; /**< type of the message */
 } jerry_debugger_send_type_t;
 
@@ -256,9 +260,8 @@ typedef struct
  */
 typedef struct
 {
-  jerry_debugger_send_header_t header; /**< message header */
   uint8_t type; /**< type of the message */
-  uint8_t string[JERRY_DEBUGGER_SEND_MAX (uint8_t)]; /**< string data */
+  uint8_t string[]; /**< string data */
 } jerry_debugger_send_string_t;
 
 /**
@@ -266,7 +269,6 @@ typedef struct
  */
 typedef struct
 {
-  jerry_debugger_send_header_t header; /**< message header */
   uint8_t type; /**< type of the message */
   uint8_t line[sizeof (uint32_t)]; /**< value data */
   uint8_t column[sizeof (uint32_t)]; /**< value data */
@@ -277,7 +279,6 @@ typedef struct
  */
 typedef struct
 {
-  jerry_debugger_send_header_t header; /**< message header */
   uint8_t type; /**< type of the message */
   uint8_t byte_code_cp[sizeof (jmem_cpointer_t)]; /**< byte code compressed pointer */
 } jerry_debugger_send_byte_code_cp_t;
@@ -307,7 +308,6 @@ typedef struct
  */
 typedef struct
 {
-  jerry_debugger_send_header_t header; /**< message header */
   uint8_t type; /**< type of the message */
   uint8_t allocated_bytes[sizeof (uint32_t)]; /**< allocated bytes */
   uint8_t byte_code_bytes[sizeof (uint32_t)]; /**< byte code bytes */
@@ -321,7 +321,6 @@ typedef struct
  */
 typedef struct
 {
-  jerry_debugger_send_header_t header; /**< message header */
   uint8_t type; /**< type of the message */
   uint8_t byte_code_cp[sizeof (jmem_cpointer_t)]; /**< byte code compressed pointer */
   uint8_t offset[sizeof (uint32_t)]; /**< breakpoint offset */
@@ -341,9 +340,8 @@ typedef struct
  */
 typedef struct
 {
-  jerry_debugger_send_header_t header; /**< message header */
   uint8_t type; /**< type of the message */
-  jerry_debugger_frame_t frames[JERRY_DEBUGGER_SEND_MAX (jerry_debugger_frame_t)]; /**< frames */
+  jerry_debugger_frame_t frames[]; /**< frames */
 } jerry_debugger_send_backtrace_t;
 
 /**
diff --git a/jerry-core/jcontext/jcontext.h b/jerry-core/jcontext/jcontext.h
index 148af8f0c9..f37ac27d2c 100644
--- a/jerry-core/jcontext/jcontext.h
+++ b/jerry-core/jcontext/jcontext.h
@@ -111,6 +111,7 @@ typedef struct
 #ifdef JERRY_DEBUGGER
   uint8_t debugger_send_buffer[JERRY_DEBUGGER_MAX_BUFFER_SIZE]; /**< buffer for sending messages */
   uint8_t debugger_receive_buffer[JERRY_DEBUGGER_MAX_BUFFER_SIZE]; /**< buffer for receiving messages */
+  uint8_t *debugger_send_buffer_payload_p; /**< start where the outgoing message can be written */
   vm_frame_ctx_t *debugger_stop_context; /**< stop only if the current context is equal to this context */
   jmem_cpointer_t debugger_byte_code_free_head; /**< head of byte code free linked list */
   jmem_cpointer_t debugger_byte_code_free_tail; /**< tail of byte code free linked list */
@@ -118,6 +119,8 @@ typedef struct
   uint16_t debugger_receive_buffer_offset; /**< receive buffer offset */
   uint16_t debugger_port; /**< debugger socket communication port */
   uint8_t debugger_message_delay; /**< call receive message when reaches zero */
+  uint8_t debugger_max_send_size; /**< maximum amount of data that can be written */
+  uint8_t debugger_max_receive_size; /**< maximum amount of data that can be received */
   int debugger_connection; /**< holds the file descriptor of the socket communication */
 #endif /* JERRY_DEBUGGER */
 
diff --git a/jerry-core/parser/js/js-parser-internal.h b/jerry-core/parser/js/js-parser-internal.h
index 06f5873dc5..dd3a7cd526 100644
--- a/jerry-core/parser/js/js-parser-internal.h
+++ b/jerry-core/parser/js/js-parser-internal.h
@@ -305,7 +305,8 @@ typedef struct
 #endif /* PARSER_DUMP_BYTE_CODE */
 
 #ifdef JERRY_DEBUGGER
-  parser_breakpoint_info_t breakpoint_info[JERRY_DEBUGGER_SEND_MAX (parser_list_t)]; /**< extra data for breakpoints */
+  /** extra data for each breakpoint */
+  parser_breakpoint_info_t breakpoint_info[JERRY_DEBUGGER_MAX_BUFFER_SIZE / sizeof (parser_breakpoint_info_t)];
   uint16_t breakpoint_info_count; /**< current breakpoint index */
   parser_line_counter_t last_breakpoint_line; /**< last line where breakpoint was inserted */
 #endif /* JERRY_DEBUGGER */
diff --git a/jerry-core/parser/js/js-parser.c b/jerry-core/parser/js/js-parser.c
index 1b31be1739..37519c3eb7 100644
--- a/jerry-core/parser/js/js-parser.c
+++ b/jerry-core/parser/js/js-parser.c
@@ -2700,7 +2700,7 @@ parser_append_breakpoint_info (parser_context_t *context_p, /**< context */
 
   context_p->status_flags |= PARSER_DEBUGGER_BREAKPOINT_APPENDED;
 
-  if (context_p->breakpoint_info_count >= JERRY_DEBUGGER_SEND_MAX (parser_list_t))
+  if (context_p->breakpoint_info_count >= JERRY_DEBUGGER_SEND_MAX (parser_breakpoint_info_t))
   {
     parser_send_breakpoints (context_p, type);
   }