diff --git a/lib/open_project/html_diff.rb b/lib/open_project/html_diff.rb
new file mode 100644
index 000000000000..6471778aec2f
--- /dev/null
+++ b/lib/open_project/html_diff.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) 2012-2024 the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
+#++
+
+module OpenProject
+ module HtmlDiff
+ extend OpenProject::TextFormatting
+
+ module_function
+
+ def from_markdown(markdown_from, markdown_to)
+ ::HTMLDiff::DiffBuilder.new(
+ format_text(markdown_from, disable_macro_expansion: true),
+ format_text(markdown_to, disable_macro_expansion: true)
+ ).build
+ .gsub(/(\n\r?)<\/ins>/, '\1')
+ .gsub(/(\n\r?)<\/del>/, '\1')
+ .gsub(/^