diff --git a/.travis.yml b/.travis.yml
index c0b78f0fe..6bfc3a4a7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,8 +5,17 @@ rvm:
   - 2.0.0
   - 2.1.7
   - 2.2.3
+  - 2.3.3
 gemfile:
-  - Gemfile.rails32
   - Gemfile.rails40
   - Gemfile.rails41
   - Gemfile.rails42
+  - Gemfile.rails50 # Min ruby 2.2.2
+matrix:
+  exclude:
+    - rvm: 1.9.3
+      gemfile: Gemfile.rails50
+    - rvm: 2.0.0
+      gemfile: Gemfile.rails50
+    - rvm: 2.1.7
+      gemfile: Gemfile.rails50
diff --git a/Gemfile b/Gemfile
deleted file mode 100644
index c74bc4694..000000000
--- a/Gemfile
+++ /dev/null
@@ -1,7 +0,0 @@
-source "https://rubygems.org"
-
-gemspec
-
-# load local gemfile
-local_gemfile = File.join(File.dirname(__FILE__), 'Gemfile.local')
-self.instance_eval(Bundler.read_file(local_gemfile)) if File.exist?(local_gemfile)
diff --git a/Gemfile b/Gemfile
new file mode 120000
index 000000000..faa0ba8bc
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1 @@
+Gemfile.rails50
\ No newline at end of file
diff --git a/Gemfile.rails32 b/Gemfile.rails32
deleted file mode 100644
index 808c331ef..000000000
--- a/Gemfile.rails32
+++ /dev/null
@@ -1,6 +0,0 @@
-source "https://rubygems.org"
-
-gemspec
-
-gem 'rails', '~> 3.2.0'
-gem 'test-unit', '~> 3.0'
diff --git a/Gemfile.rails41 b/Gemfile.rails41
index 0a7a2f156..1ea07cd22 100644
--- a/Gemfile.rails41
+++ b/Gemfile.rails41
@@ -3,4 +3,4 @@ source "https://rubygems.org"
 gemspec
 
 gem 'rails', '~> 4.1.0'
-gem 'mime-types', '~> 2.99.3'
\ No newline at end of file
+gem 'mime-types', '~> 2.99.3'
diff --git a/Gemfile.rails50 b/Gemfile.rails50
new file mode 100644
index 000000000..18e224f14
--- /dev/null
+++ b/Gemfile.rails50
@@ -0,0 +1,7 @@
+source "https://rubygems.org"
+
+gemspec
+
+gem 'rails', '~> 5.0'
+gem 'mime-types', '~> 2.99.3'
+gem 'rails-controller-testing'
diff --git a/apipie-rails.gemspec b/apipie-rails.gemspec
index 57ce5c1d6..4940f0e67 100644
--- a/apipie-rails.gemspec
+++ b/apipie-rails.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |s|
   s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
   s.require_paths = ["lib"]
 
-  s.add_development_dependency "rails", ">= 3.0.20"
+  s.add_dependency "rails", ">= 4.0"
   s.add_dependency 'json'
   s.add_development_dependency "rspec-rails", "~> 3.0"
   s.add_development_dependency "sqlite3"
diff --git a/lib/apipie/application.rb b/lib/apipie/application.rb
index e59044f14..516093c6c 100644
--- a/lib/apipie/application.rb
+++ b/lib/apipie/application.rb
@@ -54,14 +54,9 @@ def rails_routes(route_set = nil)
     # the app might be nested when using contraints, namespaces etc.
     # this method does in depth search for the route controller
     def route_app_controller(app, route, visited_apps = [])
-      visited_apps << app
-      if app.respond_to?(:controller)
-        return app.controller(route.defaults)
-      elsif app.respond_to?(:app) && !visited_apps.include?(app.app)
-        return route_app_controller(app.app, route, visited_apps)
+      if route.defaults[:controller]
+        (route.defaults[:controller].camelize + "Controller").constantize
       end
-    rescue ActionController::RoutingError
-      # some errors in the routes will not stop us here: just ignoring
     end
 
     def routes_for_action(controller, method, args)
diff --git a/lib/apipie/param_description.rb b/lib/apipie/param_description.rb
index 95e6392fd..6c3780ed1 100644
--- a/lib/apipie/param_description.rb
+++ b/lib/apipie/param_description.rb
@@ -72,9 +72,20 @@ def from_concern?
       method_description.from_concern? || @from_concern
     end
 
+    def normalized_value(value)
+      if value.is_a?(ActionController::Parameters) && !value.is_a?(Hash)
+        value.to_unsafe_hash
+      elsif value.is_a? Array
+        value.map { |v| normalized_value (v) }
+      else
+        value
+      end
+    end
+
     def validate(value)
       return true if @allow_nil && value.nil?
       return true if @allow_blank && value.blank?
+      value = normalized_value(value)
       if (!@allow_nil && value.nil?) || !@validator.valid?(value)
         error = @validator.error
         error = ParamError.new(error) unless error.is_a? StandardError
@@ -83,6 +94,7 @@ def validate(value)
     end
 
     def process_value(value)
+      value = normalized_value(value)
       if @validator.respond_to?(:process_value)
         @validator.process_value(value)
       else
diff --git a/spec/controllers/apipies_controller_spec.rb b/spec/controllers/apipies_controller_spec.rb
index 0bbfcb1e2..867bf0a8d 100644
--- a/spec/controllers/apipies_controller_spec.rb
+++ b/spec/controllers/apipies_controller_spec.rb
@@ -12,37 +12,37 @@
     end
 
     it "succeeds on version details" do
-      get :index, :version => "2.0"
+      get :index, :params => { :version => "2.0" }
 
       assert_response :success
     end
 
     it "returns not_found on wrong version" do
-      get :index, :version => "wrong_version"
+      get :index, :params => { :version => "wrong_version" }
 
       assert_response :not_found
     end
 
     it "succeeds on resource details" do
-      get :index, :version => "2.0", :resource => "architectures"
+      get :index, :params => { :version => "2.0", :resource => "architectures" }
 
       assert_response :success
     end
 
     it "returns not_found on wrong resource" do
-      get :index, :version => "2.0", :resource => "wrong_resource"
+      get :index, :params => { :version => "2.0", :resource => "wrong_resource" }
 
       assert_response :not_found
     end
 
     it "succeeds on method details" do
-      get :index, :version => "2.0", :resource => "architectures", :method => "index"
+      get :index, :params => { :version => "2.0", :resource => "architectures", :method => "index" }
 
       assert_response :success
     end
 
     it "returns not_found on wrong method" do
-      get :index, :version => "2.0", :resource => "architectures", :method => "wrong_method"
+      get :index, :params => { :version => "2.0", :resource => "architectures", :method => "wrong_method" }
 
       assert_response :not_found
     end
@@ -215,17 +215,17 @@
     it "uses the file in cache dir instead of generating the content on runtime" do
       get :index
       expect(response.body).to eq("apidoc.html cache v1")
-      get :index, :version => 'v1'
+      get :index, :params => { :version => 'v1' }
       expect(response.body).to eq("apidoc.html cache v1")
-      get :index, :version => 'v2'
+      get :index, :params => { :version => 'v2' }
       expect(response.body).to eq("apidoc.html cache v2")
-      get :index, :version => 'v1', :format => "html"
+      get :index, :params => { :version => 'v1', :format => "html" }
       expect(response.body).to eq("apidoc.html cache v1")
-      get :index, :version => 'v1', :format => "json"
+      get :index, :params => { :version => 'v1', :format => "json" }
       expect(response.body).to eq("apidoc.json cache")
-      get :index, :version => 'v1', :format => "html", :resource => "resource"
+      get :index, :params => { :version => 'v1', :format => "html", :resource => "resource" }
       expect(response.body).to eq("resource.html cache")
-      get :index, :version => 'v1', :format => "html", :resource => "resource", :method => "method"
+      get :index, :params => { :version => 'v1', :format => "html", :resource => "resource", :method => "method" }
       expect(response.body).to eq("method.html cache")
     end
 
diff --git a/spec/controllers/concerns_controller_spec.rb b/spec/controllers/concerns_controller_spec.rb
index a80d5c5fd..c1f5b7b33 100644
--- a/spec/controllers/concerns_controller_spec.rb
+++ b/spec/controllers/concerns_controller_spec.rb
@@ -8,7 +8,7 @@
   end
 
   it "should reply to valid request" do
-    get :show, :id => '5', :session => "secret_hash"
+    get :show, :params => { :id => '5' }, :session => { :user_id => "secret_hash" }
     assert_response :success
   end
 
diff --git a/spec/controllers/users_controller_spec.rb b/spec/controllers/users_controller_spec.rb
index 9e5e9c5db..239a278d9 100644
--- a/spec/controllers/users_controller_spec.rb
+++ b/spec/controllers/users_controller_spec.rb
@@ -66,7 +66,7 @@ def compare_hashes(h1, h2)
       end
 
       it "should reply to valid request" do
-        get :show, :id => '5', :session => "secret_hash"
+        get :show, :params => { :id => '5', :session => "secret_hash" }
         assert_response :success
       end
 
@@ -92,17 +92,17 @@ def reload_controllers
           end
 
           it "should reply to valid request" do
-            expect { get :show, :id => 5, :session => "secret_hash" }.not_to raise_error
+            expect { get :show, :params => { :id => 5, :session => "secret_hash" }}.not_to raise_error
             assert_response :success
           end
 
           it "should fail if required parameter is missing" do
-            expect { get :show, :id => 5 }.to raise_error(Apipie::ParamMissing, /session_parameter_is_required/)
+            expect { get :show, :params => { :id => 5 }}.to raise_error(Apipie::ParamMissing, /session_parameter_is_required/)
           end
 
           it "should pass if required parameter has wrong type" do
-            expect { get :show, :id => 5, :session => "secret_hash" }.not_to raise_error
-            expect { get :show, :id => "ten", :session => "secret_hash" }.not_to raise_error
+            expect { get :show, :params => { :id => 5 , :session => "secret_hash" }}.not_to raise_error
+            expect { get :show, :params => { :id => "ten" , :session => "secret_hash" }}.not_to raise_error
           end
 
         end
@@ -115,12 +115,12 @@ def reload_controllers
           end
 
           it "should reply to valid request" do
-            expect { get :show, :id => 5, :session => "secret_hash" }.not_to raise_error
+            expect { get :show, :params => { :id => 5, :session => 'secret_hash' }}.not_to raise_error
             assert_response :success
           end
 
           it "should fail if extra parameter is passed in" do
-            expect { get :show, :id => 5, :session => "secret_hash", :badparam => 'badfoo' }.to raise_error(Apipie::UnknownParam, /\bbadparam\b/)
+            expect { get :show, :params => { :id => 5 , :badparam => 'badfoo', :session => "secret_hash" }}.to raise_error(Apipie::UnknownParam, /\bbadparam\b/)
           end
         end
 
@@ -132,81 +132,75 @@ def reload_controllers
           end
 
           it "should reply to valid request" do
-            get :show, :id => '5', :session => "secret_hash"
+            get :show, :params => { :id => '5', :session => "secret_hash" }
             assert_response :success
           end
 
           it "should work with nil value for a required hash param" do
             expect {
-              get :show, :id => '5', :session => "secret_hash", :hash_param => {:dummy_hash => nil}
+              get :show, :params => { :id => '5', :session => "secret_hash", :hash_param => {:dummy_hash => nil} }
             }.to raise_error(Apipie::ParamInvalid, /dummy_hash/)
             assert_response :success
           end
 
           it "should fail if required parameter is missing" do
-            expect { get :show, :id => 5 }.to raise_error(Apipie::ParamMissing, /session_parameter_is_required/)
+            expect { get :show, :params => { :id => 5 }}.to raise_error(Apipie::ParamMissing, /session_parameter_is_required/)
           end
 
           it "should work with custom Type validator" do
             expect {
               get :show,
-                  :id => "not a number",
-                  :session => "secret_hash"
+                  :params => { :id => "not a number", :session => "secret_hash" }
             }.to raise_error(Apipie::ParamError, /id/) # old-style error rather than ParamInvalid
           end
 
           it "should work with Regexp validator" do
-            get :show,
-                :id => 5,
-                :session => "secret_hash",
-                :regexp_param => "24 years"
+            get :show, :params => { :id => 5, :session => "secret_hash", :regexp_param => "24 years" }
             assert_response :success
 
             expect {
-              get :show,
-                  :id => 5,
-                  :session => "secret_hash",
-                  :regexp_param => "ten years"
+              get :show, :params => { :id => 5,
+                                      :session => "secret_hash",
+                                      :regexp_param => "ten years" }
             }.to raise_error(Apipie::ParamInvalid, /regexp_param/)
           end
 
           it "should work with Array validator" do
-            get :show, :id => 5, :session => "secret_hash", :array_param => "one"
-            assert_response :success
-            get :show, :id => 5, :session => "secret_hash", :array_param => "two"
+            get :show, :params => { :id => 5, :session => "secret_hash", :array_param => "one" }
             assert_response :success
-            get :show, :id => 5, :session => "secret_hash", :array_param => '1'
+            get :show, :params => { :id => 5, :session => "secret_hash", :array_param => "two" }
             assert_response :success
-            get :show, :id => 5, :session => "secret_hash", :boolean_param => false
+            get :show, :params => { :id => 5, :session => "secret_hash", :array_param => '1' }
             assert_response :success
 
             expect {
-              get :show,
-                  :id => 5,
-                  :session => "secret_hash",
-                  :array_param => "blabla"
+              get :show, :params => { :id => 5,
+                                      :session => "secret_hash",
+                                      :array_param => "blabla" }
             }.to raise_error(Apipie::ParamInvalid, /array_param/)
 
             expect {
-              get :show,
-                  :id => 5,
-                  :session => "secret_hash",
-                  :array_param => 3
+              get :show, :params => {
+                :id => 5,
+                :session => "secret_hash",
+                :array_param => 3 }
             }.to raise_error(Apipie::ParamInvalid, /array_param/)
           end
 
           it "should work with Proc validator" do
             expect {
               get :show,
-                  :id => 5,
-                  :session => "secret_hash",
-                  :proc_param => "asdgsag"
+                  :params => {
+                    :id => 5,
+                    :session => "secret_hash",
+                    :proc_param => "asdgsag" }
             }.to raise_error(Apipie::ParamInvalid, /proc_param/)
 
             get :show,
-                :id => 5,
-                :session => "secret_hash",
-                :proc_param => "param value"
+                :params => {
+                  :id => 5,
+                  :session => "secret_hash",
+                  :proc_param => "param value"}
             assert_response :success
           end
 
@@ -262,7 +256,7 @@ def reload_controllers
                    :pass => "12345",
                    :membership => "standard",
                  },
-                 :facts => nil
+                 :facts => { :test => 'test' }
             assert_response :success
           end
 
@@ -305,21 +299,21 @@ def reload_controllers
               it "should raise an error" do
                 expect{
                   put :update,
-                    {
-                      :id => 5,
-                      :user => {
-                        :name => "root",
-                        :pass => "12345"
-                      },
-                      :comments => [
-                        {
-                          :comment => 'comment1'
+                      :params => {
+                        :id => 5,
+                        :user => {
+                          :name => "root",
+                          :pass => "12345"
                         },
-                        {
-                          :comment => {:bad_input => 5}
-                        }
-                      ]
-                    }
+                        :comments => [
+                          {
+                            :comment => {:bad_input => 4}
+                          },
+                          {
+                            :comment => {:bad_input => 5}
+                          }
+                        ]
+                      }
                 }.to raise_error(Apipie::ParamInvalid)
               end
             end
@@ -708,13 +702,16 @@ class IgnoredController < ApplicationController; end
 
   describe "Parameter processing / extraction" do
     before do
+      Apipie.configuration.validate = true
       Apipie.configuration.process_params = true
+      controllers_dirname = File.expand_path('../dummy/app/controllers', File.dirname(__FILE__))
+      Dir.glob("#{controllers_dirname}/**/*") { |file| load(file) if File.file?(file) }
     end
 
     it "process correctly the parameters" do
-      post :create, {:user => {:name => 'dummy', :pass => 'dummy', :membership => 'standard'}, :facts => nil}
+      post :create, :user => {:name => 'dummy', :pass => 'dummy', :membership => 'standard' }, :facts => {:test => 'test'}
 
-      expect(assigns(:api_params).with_indifferent_access).to eq({:user => {:name=>"dummy", :pass=>"dummy", :membership=>"standard"}, :facts => nil}.with_indifferent_access)
+      expect(assigns(:api_params).with_indifferent_access).to eq({:user => {:name=>"dummy", :pass=>"dummy", :membership=>"standard"}, :facts => {:test => 'test'}}.with_indifferent_access)
     end
 
     it "ignore not described parameters" do
diff --git a/spec/dummy/config/environments/development.rb b/spec/dummy/config/environments/development.rb
index 4a797a03c..0be8bfa65 100644
--- a/spec/dummy/config/environments/development.rb
+++ b/spec/dummy/config/environments/development.rb
@@ -21,5 +21,8 @@
 
   # Only use best-standards-support built into browsers
   config.action_dispatch.best_standards_support = :builtin
+
+  # Do not eager load code on boot. (Rails 5)
+  config.eager_load = false
 end
 
diff --git a/spec/dummy/config/environments/production.rb b/spec/dummy/config/environments/production.rb
index cbdb27757..1ac38aea8 100644
--- a/spec/dummy/config/environments/production.rb
+++ b/spec/dummy/config/environments/production.rb
@@ -46,4 +46,7 @@
 
   # Send deprecation notices to registered listeners
   config.active_support.deprecation = :notify
+
+  # Eager load code on boot (Rails 5)
+  config.eager_load = true
 end
diff --git a/spec/dummy/config/environments/test.rb b/spec/dummy/config/environments/test.rb
index 768d8f044..5d38a3157 100644
--- a/spec/dummy/config/environments/test.rb
+++ b/spec/dummy/config/environments/test.rb
@@ -32,4 +32,7 @@
 
   # Print deprecation notices to the stderr
   config.active_support.deprecation = :stderr
+
+  # Do not eager load code on boot. (Rails 5)
+  config.eager_load = false
 end
diff --git a/spec/dummy/config/routes.rb b/spec/dummy/config/routes.rb
index 2d3d48b01..d63cf976b 100644
--- a/spec/dummy/config/routes.rb
+++ b/spec/dummy/config/routes.rb
@@ -10,7 +10,7 @@
       end
       resources :concerns, :only => [:index, :show]
       namespace :files do
-        get '/*file_path', to: :download, format: false
+        get '/*file_path', format: false, :action => 'download'
       end
       resources :twitter_example do
         collection do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 9938dd5ad..36e1c85a6 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -9,6 +9,34 @@
 
 require 'apipie-rails'
 
+module Rails4Compatibility
+  module Testing
+    def process_with_rails4_compat(*args)
+      compatible_request(*args) { |*new_args| process_without_rails4_compat(*new_args) }
+    end
+
+    def self.included(base)
+      base.alias_method_chain :process, :rails4_compat
+    end
+
+    def compatible_request(method, action, hash = {})
+      if hash.is_a?(Hash)
+        if Gem::Version.new(Rails.version) < Gem::Version.new('5.0.0')
+          hash = hash.dup
+          hash.merge!(hash.delete(:params) || {})
+        elsif hash.key?(:params)
+          hash = { :params => hash }
+        end
+      end
+      if hash.empty?
+        yield method, action
+      else
+        yield method, action, hash
+      end
+    end
+  end
+end
+
 # Requires supporting ruby files with custom matchers and macros, etc,
 # in spec/support/ and its subdirectories.
 Dir[File.expand_path("../support/**/*.rb", __FILE__)].each {|f| require f}
@@ -41,3 +69,7 @@
   #     end
   config.infer_spec_type_from_file_location!
 end
+
+require 'action_controller/test_case.rb'
+# TODO: replace with prepend once we deprecate ruby 2.0.0
+ActionController::TestCase::Behavior.send(:include, Rails4Compatibility::Testing)