diff --git a/publify_textfilter_code.gemspec b/publify_textfilter_code.gemspec
index b9d0d61..9c63e92 100644
--- a/publify_textfilter_code.gemspec
+++ b/publify_textfilter_code.gemspec
@@ -23,6 +23,7 @@ Gem::Specification.new do |s|
   s.add_dependency "publify_core", "~> 10.0.0"
 
   s.add_development_dependency "appraisal", "~> 2.3"
+  s.add_development_dependency "json", "~> 2.0"
   s.add_development_dependency "rspec-rails", "~> 7.1"
   s.add_development_dependency "rubocop", "~> 1.91.0"
   s.add_development_dependency "rubocop-capybara", "~> 3.0.0"