diff --git a/core/assets/js/feldspar_app.js b/core/assets/js/feldspar_app.js
index 2b8a2962e..460beaf00 100644
--- a/core/assets/js/feldspar_app.js
+++ b/core/assets/js/feldspar_app.js
@@ -2,6 +2,8 @@ export const FeldsparApp = {
   mounted() {
     console.log("FeldsparApp MOUNTED");
 
+    console.log(this.el.dataset);
+
     const iframe = this.getIframe();
     iframe.addEventListener("load", () => {
       this.onFrameLoaded();
@@ -19,7 +21,11 @@ export const FeldsparApp = {
     this.channel.port1.onmessage = (e) => {
       this.handleMessage(e);
     };
-    this.getIframe().contentWindow.postMessage("init", "*", [
+
+    let action = "live-init";
+    let locale = this.el.dataset.locale;
+
+    this.getIframe().contentWindow.postMessage({ action, locale }, "*", [
       this.channel.port2,
     ]);
   },
diff --git a/core/lib/core_web/live_locale.ex b/core/lib/core_web/live_locale.ex
index 1c94999a9..2eec8d0ed 100644
--- a/core/lib/core_web/live_locale.ex
+++ b/core/lib/core_web/live_locale.ex
@@ -28,7 +28,6 @@ defmodule CoreWeb.LiveLocale do
       def mount(params, %{"locale" => locale} = session, socket) do
         Gettext.put_locale(CoreWeb.Gettext, locale)
         Gettext.put_locale(Timex.Gettext, locale)
-        Gettext.get_locale()
         super(params, session, socket)
       end
     end
diff --git a/core/systems/feldspar/app_page.ex b/core/systems/feldspar/app_page.ex
index 084b6fd28..1d412e27f 100644
--- a/core/systems/feldspar/app_page.ex
+++ b/core/systems/feldspar/app_page.ex
@@ -24,7 +24,7 @@ defmodule Systems.Feldspar.AppPage do
   def render(assigns) do
     ~H"""
     <.stripped menus={@menus} footer?={false}>
-      <.app_view url={@app_url} />
+      <.app_view url={@app_url} locale={Gettext.get_locale()} />
     </.stripped>
     """
   end
diff --git a/core/systems/feldspar/app_view.ex b/core/systems/feldspar/app_view.ex
index 4ec810bab..cdee6f84b 100644
--- a/core/systems/feldspar/app_view.ex
+++ b/core/systems/feldspar/app_view.ex
@@ -2,6 +2,7 @@ defmodule Systems.Feldspar.AppView do
   use CoreWeb, :html
 
   attr(:url, :string, required: true)
+  attr(:locale, :string, required: true)
 
   def app_view(assigns) do
     ~H"""
@@ -10,7 +11,7 @@ defmodule Systems.Feldspar.AppView do
         Changing the preceding siblings of the iframe would result in a reload of the iframe
         due to Morphdom (https://github.com/patrick-steele-idem/morphdom/issues/200).
           --%>
-        <div class="w-full h-full" phx-update="ignore"  id="web-app-frame" phx-hook="FeldsparApp" data-src={@url}>
+        <div class="w-full h-full" phx-update="ignore"  id="web-app-frame" phx-hook="FeldsparApp" data-locale={@locale} data-src={@url}>
           <iframe class="w-full h-full"></iframe>
         </div>
       </div>
diff --git a/core/systems/feldspar/tool_model.ex b/core/systems/feldspar/tool_model.ex
index b9d68fd46..cb191f340 100644
--- a/core/systems/feldspar/tool_model.ex
+++ b/core/systems/feldspar/tool_model.ex
@@ -50,7 +50,10 @@ defmodule Systems.Feldspar.ToolModel do
     def launcher(%{archive_ref: archive_ref}) when is_binary(archive_ref) do
       %{
         function: &Feldspar.AppView.app_view/1,
-        props: %{url: archive_ref <> "/index.html"}
+        props: %{
+          url: archive_ref <> "/index.html",
+          locale: Gettext.get_locale(CoreWeb.Gettext)
+        }
       }
     end