diff --git a/include/communication/EmscriptenCommunication.h b/include/communication/EmscriptenCommunication.h
index fc2a6897df..d6d07baed3 100644
--- a/include/communication/EmscriptenCommunication.h
+++ b/include/communication/EmscriptenCommunication.h
@@ -21,6 +21,7 @@ class EmscriptenCommunication : public CommandLine
 {
 private:
     std::string progress_handler_; ///< Handler for progress messages.
+    std::string gcode_prefix_handler_; /// <Handler for getting gcode_prefix.
     std::string slice_info_handler_; ///< Handler for slice information messages.
 
     /**
@@ -42,6 +43,11 @@ class EmscriptenCommunication : public CommandLine
      */
     void sendProgress(double progress) const override;
 
+    /**
+     * \brief Sends GcodeHeader
+     */
+    void sendGCodePrefix(const std::string& prefix) const override;
+
     /**
      * \brief Initiates the slicing of the next item.
      */
diff --git a/src/communication/CommandLine.cpp b/src/communication/CommandLine.cpp
index 493266ae8d..51a016c82a 100644
--- a/src/communication/CommandLine.cpp
+++ b/src/communication/CommandLine.cpp
@@ -193,7 +193,7 @@ void CommandLine::sliceNext()
                     force_read_nondefault = false;
                 }
 #ifdef __EMSCRIPTEN__
-                else if (argument.starts_with("--progress_cb") || argument.starts_with("--slice_info_cb"))
+                else if (argument.starts_with("--progress_cb") || argument.starts_with("--slice_info_cb") || argument.starts_with("--gcode_prefix_cb"))
                 {
                     argument_index++;
                     argument = arguments_[argument_index];
diff --git a/src/communication/EmscriptenCommunication.cpp b/src/communication/EmscriptenCommunication.cpp
index 140f47316d..25d0a31448 100644
--- a/src/communication/EmscriptenCommunication.cpp
+++ b/src/communication/EmscriptenCommunication.cpp
@@ -33,6 +33,15 @@ EmscriptenCommunication::EmscriptenCommunication(const std::vector<std::string>&
     {
         slice_info_handler_ = *ranges::next(slice_info_flag);
     }
+    if (auto gcode_prefix_flag = ranges::find(arguments_, "--gcode_prefix_cb"); gcode_prefix_flag != arguments_.end())
+    {
+        gcode_prefix_handler_ = *ranges::next(gcode_prefix_flag);
+    }
+}
+
+void EmscriptenCommunication::sendGCodePrefix(const std::string& prefix) const
+{
+    emscripten_run_script(fmt::format("globalThis[\"{}\"]({})", gcode_prefix_handler_, prefix).c_str());
 }
 
 void EmscriptenCommunication::sendProgress(double progress) const