diff --git a/Gemfile b/Gemfile
index 642fc335..49e01577 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
 gemspec
 
-gem "rails", github: "rails/rails"
+gem "json"
 gem "rack", github: "rack/rack"
 gem "rack-session", github: "rack/rack-session"
 
diff --git a/lib/web_console.rb b/lib/web_console.rb
index 38526094..51fb34da 100644
--- a/lib/web_console.rb
+++ b/lib/web_console.rb
@@ -30,4 +30,4 @@ def self.logger
   end
 end
 
-require "web_console/railtie"
+require "web_console/railtie" if defined?(::Rails::Railtie)
diff --git a/lib/web_console/exception_mapper.rb b/lib/web_console/exception_mapper.rb
index e750fc3a..c4317904 100644
--- a/lib/web_console/exception_mapper.rb
+++ b/lib/web_console/exception_mapper.rb
@@ -50,7 +50,7 @@ def guess_the_first_application_binding
         @bindings.find do |binding|
           source_location = SourceLocation.new(binding)
           source_location.path.to_s.start_with?(Rails.root.to_s)
-        end
+        end if defined?(Rails.root) && Rails.root
       end
   end
 end
diff --git a/lib/web_console/middleware.rb b/lib/web_console/middleware.rb
index 256e1514..7e9c6739 100644
--- a/lib/web_console/middleware.rb
+++ b/lib/web_console/middleware.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "active_support/core_ext/string/strip"
+require "json"
 
 module WebConsole
   class Middleware
diff --git a/test/templates/config.ru b/test/templates/config.ru
index b89f8376..87a7a0de 100644
--- a/test/templates/config.ru
+++ b/test/templates/config.ru
@@ -1,3 +1,4 @@
+require "json"
 require "web_console/testing/fake_middleware"
 
 TEST_ROOT = Pathname(__FILE__).dirname