diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6eeb82b..7d2c0d1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ This project adheres to [Semantic Versioning](http://semver.org/) and [Keep a Ch
 ---
 
 ### New
+- Support for options hash for `*_rfc6570` to support Rails Engines.
 
 ### Changes
 
@@ -17,6 +18,7 @@ This project adheres to [Semantic Versioning](http://semver.org/) and [Keep a Ch
 ### Fixes
 
 - Fix up `RouteSet#to_rfc6570` and `NamedRouteCollection#to_rfc6570`
+- Fix up `*_path_rfc6570` to include Rails Engines mount point.
 
 ### Breaks
 
diff --git a/lib/rails/rfc6570.rb b/lib/rails/rfc6570.rb
index cf5bbeb..31b1b30 100644
--- a/lib/rails/rfc6570.rb
+++ b/lib/rails/rfc6570.rb
@@ -52,15 +52,15 @@ def define_rfc6570_helpers(name, route, mod, set)
           end
 
           mod.module_eval do
-            define_method(rfc6570_name) do |**opts|
+            define_method(rfc6570_name) do |opts = {}|
               route.to_rfc6570(**opts, ctx: self)
             end
 
-            define_method(rfc6570_url_name) do |**opts|
+            define_method(rfc6570_url_name) do |opts = {}|
               route.to_rfc6570(**opts, ctx: self, path_only: false)
             end
 
-            define_method(rfc6570_path_name) do |**opts|
+            define_method(rfc6570_path_name) do |opts = {}|
               route.to_rfc6570(**opts, ctx: self, path_only: true)
             end
           end
diff --git a/lib/rails/rfc6570/formatter.rb b/lib/rails/rfc6570/formatter.rb
index 23cde98..9d8d254 100644
--- a/lib/rails/rfc6570/formatter.rb
+++ b/lib/rails/rfc6570/formatter.rb
@@ -25,19 +25,16 @@ def evaluate(ctx:, ignore: %w[format], **kwargs)
           end
         end
 
-        if kwargs.fetch(:path_only, false)
-          ::Addressable::Template.new parts.join
-        else
-          options = ctx.url_options.merge(kwargs)
-          options[:path] = parts.join
-
-          if (osn = options.delete(:original_script_name))
-            options[:script_name] = osn + options[:script_name]
-          end
+        options = ctx.url_options.merge(kwargs)
+        options[:path] = parts.join
+        options[:only_path] = kwargs.fetch(:path_only, false)
 
-          ::Addressable::Template.new \
-            ActionDispatch::Http::URL.url_for(options)
+        if (osn = options.delete(:original_script_name))
+          options[:script_name] = osn + options[:script_name]
         end
+
+        ::Addressable::Template.new \
+          ActionDispatch::Http::URL.url_for(options)
       end
 
       def symbol(node, prefix: nil, suffix: nil)
diff --git a/spec/dummy/dummy_engine/app/controllers/dummy_engine/application_controller.rb b/spec/dummy/dummy_engine/app/controllers/dummy_engine/application_controller.rb
new file mode 100644
index 0000000..b5ba86d
--- /dev/null
+++ b/spec/dummy/dummy_engine/app/controllers/dummy_engine/application_controller.rb
@@ -0,0 +1,4 @@
+module DummyEngine
+  class ApplicationController < ActionController::API
+  end
+end
diff --git a/spec/dummy/dummy_engine/lib/dummy_engine.rb b/spec/dummy/dummy_engine/lib/dummy_engine.rb
new file mode 100644
index 0000000..b84cd40
--- /dev/null
+++ b/spec/dummy/dummy_engine/lib/dummy_engine.rb
@@ -0,0 +1,5 @@
+module DummyEngine
+  class Engine < ::Rails::Engine
+    isolate_namespace DummyEngine
+  end
+end
diff --git a/spec/rails/rfc6570_spec.rb b/spec/rails/rfc6570_spec.rb
index ab25177..f008732 100644
--- a/spec/rails/rfc6570_spec.rb
+++ b/spec/rails/rfc6570_spec.rb
@@ -1,11 +1,17 @@
 # frozen_string_literal: true
 
 require 'spec_helper'
+require_relative '../dummy/dummy_engine/lib/dummy_engine'
+require_relative '../dummy/dummy_engine/app/controllers/dummy_engine/application_controller'
 
 ActiveSupport::Inflector.inflections(:en) do |inflect|
   inflect.acronym 'API'
 end
 
+DummyEngine::Engine.routes.draw do
+  get '/action' => 'api#action', as: :action
+end
+
 Dummy::Application.routes.draw do
   get '/' => 'api#index', as: :root
 
@@ -20,6 +26,8 @@
   get '/path/*capture/:title' => 'api#index', as: :test4
   get '/path(/*capture)/:title' => 'api#index', as: :test5
   get '/path(/*capture)(/:title)' => 'api#index', as: :test6
+
+  mount DummyEngine::Engine => '/dummy_engine'
 end
 
 class APIController < ApplicationController
@@ -49,6 +57,18 @@ def default_url_options
   end
 end
 
+class DummyEngine::APIController < DummyEngine::ApplicationController
+  rfc6570_params action: %i[param3]
+  def action
+    render json: {
+      ref: action_path,
+      template: action_rfc6570,
+      template_url: action_url_rfc6570,
+      template_path: action_path_rfc6570,
+    }
+  end
+end
+
 describe Rails::RFC6570, type: :request do
   let(:host) { 'http://www.example.com' }
   let(:json) { JSON.parse response.body }
@@ -58,7 +78,7 @@ def default_url_options
 
     it 'returns list of all parsed and named routes' do
       expect(json.keys).to match_array \
-        %w[root action test1 test2 test3 test4 test5 test6]
+        %w[root action test1 test2 test3 test4 test5 test6 dummy_engine]
     end
 
     it 'includes known parameters' do
@@ -134,4 +154,24 @@ def default_url_options
       end
     end
   end
+
+  context 'action in Rails Engine' do
+    before { get '/dummy_engine/action', headers: headers }
+
+    it 'includes URL helpers' do
+      expect(response).to have_http_status :ok
+    end
+
+    it 'allows to return and render templates' do
+      expect(json['template']).to eq "#{host}/dummy_engine/action{?param3}"
+    end
+
+    it 'allows to return and render url templates' do
+      expect(json['template_url']).to eq "#{host}/dummy_engine/action{?param3}"
+    end
+
+    it 'allows to return and render path templates' do
+      expect(json['template_path']).to eq '/dummy_engine/action{?param3}'
+    end
+  end
 end