diff --git a/app/ui/extensions/__init__.py b/app/ui/extensions/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/app/ui/extensions/management.py b/app/ui/extensions/management.py
new file mode 100644
index 00000000..fc819c98
--- /dev/null
+++ b/app/ui/extensions/management.py
@@ -0,0 +1,149 @@
+# -*- coding: utf-8 -*-
+#
+# The MIT License (MIT)
+#
+# Copyright (c) 2023 Dmitriy Yefremov
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+# Author: Dmitriy Yefremov
+#
+
+
+import os
+import pkgutil
+
+import requests
+
+from app.commons import log, run_task, run_idle
+from gi.repository import Gtk, GLib
+
+from app.ui.dialogs import get_message
+from app.ui.uicommons import HeaderBar
+
+EXT_URL = "https://api.github.com/repos/DYefremov/demoneditor-extensions/contents/extensions"
+HEADERS = {"User-Agent": "Mozilla/5.0 (X11; Linux i686; rv:112.0) Gecko/20100101 Firefox/112.0",
+           "Accept": "application/json"}
+
+
+class ExtensionManager(Gtk.Window):
+
+    def __init__(self, app, **kwargs):
+        super().__init__(title=get_message("Extensions"), icon_name="demon-editor", application=app,
+                         transient_for=app.app_window, destroy_with_parent=True,
+                         window_position=Gtk.WindowPosition.CENTER_ON_PARENT,
+                         default_width=560, default_height=320, modal=True, **kwargs)
+
+        self._app = app
+
+        titles = (get_message("Title"), get_message("Description"), get_message("Status"))
+        margin = {"margin_start": 5, "margin_end": 5, "margin_top": 5, "margin_bottom": 5}
+
+        self._model = Gtk.ListStore.new((str, str, str, str))
+        self._model.connect("row-deleted", self.on_model_changed)
+        self._model.connect("row-inserted", self.on_model_changed)
+        self._view = Gtk.TreeView(activate_on_single_click=True, enable_grid_lines=Gtk.TreeViewGridLines.BOTH)
+        self._view.set_model(self._model)
+
+        for i, t in enumerate(titles):
+            renderer = Gtk.CellRendererText(xalign=0.05)
+            column = Gtk.TreeViewColumn(title=t, cell_renderer=renderer, text=i)
+            column.set_resizable(True)
+            column.set_expand(True)
+            column.set_alignment(0.5)
+            column.set_min_width(50)
+            self._view.append_column(column)
+
+        main_box = Gtk.Box(spacing=5, orientation=Gtk.Orientation.VERTICAL)
+        frame = Gtk.Frame(shadow_type=Gtk.ShadowType.IN, **margin)
+        data_box = Gtk.Box(spacing=5, orientation=Gtk.Orientation.VERTICAL, **margin)
+        # Status bar.
+        status_box = Gtk.Box(spacing=5, orientation=Gtk.Orientation.HORIZONTAL, margin_start=5, margin_left=5)
+        count_icon = Gtk.Image.new_from_icon_name("document-properties", Gtk.IconSize.SMALL_TOOLBAR)
+        status_box.pack_start(count_icon, False, False, 0)
+        self._count_label = Gtk.Label(label="0", width_chars=4, xalign=0)
+        status_box.pack_start(self._count_label, False, False, 0)
+
+        data_box.pack_end(status_box, False, True, 0)
+        data_box.pack_start(self._view, True, True, 0)
+        frame.add(data_box)
+        self.add(main_box)
+
+        # Header and toolbar.
+        download_button = Gtk.Button.new_from_icon_name("go-bottom-symbolic", Gtk.IconSize.BUTTON)
+        download_button.set_tooltip_text(get_message("Download"))
+        remove_button = Gtk.Button.new_from_icon_name("user-trash-symbolic", Gtk.IconSize.BUTTON)
+        remove_button.set_tooltip_text(get_message("Remove"))
+
+        if app.app_settings.use_header_bar:
+            header = HeaderBar()
+            header.pack_start(download_button)
+            header.pack_start(remove_button)
+
+            self.set_titlebar(header)
+            header.show_all()
+        else:
+            toolbar = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL)
+            toolbar.get_style_context().add_class("primary-toolbar")
+            button_box = Gtk.Box(spacing=5, orientation=Gtk.Orientation.HORIZONTAL, **margin)
+            button_box.pack_start(download_button, False, False, 0)
+            button_box.pack_start(remove_button, False, False, 0)
+            toolbar.pack_start(button_box, True, True, 0)
+            main_box.pack_start(toolbar, False, False, 0)
+
+        main_box.pack_start(frame, True, True, 0)
+        main_box.show_all()
+
+        self.update()
+
+    def get_installed(self):
+        ext_path = f"{self._app.app_settings.default_data_path}tools{os.sep}extensions"
+        ext_paths = [f"{os.path.dirname(__file__)}{os.sep}", ext_path, "extensions"]
+
+        return {name for importer, name, is_package in pkgutil.iter_modules(ext_paths) if is_package}
+
+    @run_task
+    def update(self):
+        installed = self.get_installed()
+        extensions = []
+        with requests.get(url=EXT_URL, headers=HEADERS, stream=True) as resp:
+            if resp.status_code == 200:
+                try:
+                    for f in resp.json():
+                        if f.get("type") == "dir":
+                            name = f.get("name")
+                            extensions.append((name, None, "Installed" if name in installed else None, None))
+                except ValueError as e:
+                    log(f"ExtensionManager [update] error: {e}")
+            else:
+                log(f"ExtensionManager [update] error: {resp.reason}")
+
+        self.update_data(extensions)
+
+    @run_idle
+    def update_data(self, data):
+        self._model.clear()
+        [self._model.append(e) for e in data]
+
+    def on_model_changed(self, model, path, itr=None):
+        self._count_label.set_text(str(len(model)))
+
+
+if __name__ == "__main__":
+    pass
diff --git a/app/ui/main.py b/app/ui/main.py
index 8a6bfbc5..503a90e3 100644
--- a/app/ui/main.py
+++ b/app/ui/main.py
@@ -682,8 +682,12 @@ class Application(Gtk.Application):
 
     def init_extensions(self, builder):
         import pkgutil
+        from app.ui.extensions.management import ExtensionManager
         # Extensions (Plugins) section.
         ext_section = builder.get_object(f"{'mac_' if IS_DARWIN else ''}extension_section")
+        self.set_action("on_extension_manager", lambda a, v: ExtensionManager(self).show())
+        ext_section.append_item(Gio.MenuItem.new(get_message("Extension Manager"), "app.on_extension_manager"))
+
         ext_path = f"{self._settings.default_data_path}tools{os.sep}extensions"
         ext_paths = [f"{os.path.dirname(__file__)}{os.sep}extensions", ext_path, "extensions"]
         extensions = {}