diff --git a/lib/asciidoctor-custom-extensions.rb b/lib/asciidoctor-custom-extensions.rb
new file mode 100644
index 0000000..8c6af68
--- /dev/null
+++ b/lib/asciidoctor-custom-extensions.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require 'asciidoctor'
+require 'asciidoctor/extensions'
+
+require_relative './asciidoctor/custom_extensions/chat_block_processor'
+
+Asciidoctor::Extensions.register do
+  block ChatBlock if @document.basebackend? 'html'
+end