diff --git a/lib/rage/rspec.rb b/lib/rage/rspec.rb
new file mode 100644
index 00000000..8d0656a6
--- /dev/null
+++ b/lib/rage/rspec.rb
@@ -0,0 +1,177 @@
+# frozen_string_literal: true
+
+require "rack/test"
+require "json"
+
+# set up environment
+ENV["RAGE_ENV"] ||= ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "test"
+
+# load the app
+require "bundler/setup"
+require "rage"
+require_relative "#{Rage.root}/config/application"
+
+# verify the environment
+abort("The test suite is running in #{Rage.env} mode instead of 'test'!") unless Rage.env.test?
+
+# mock fiber methods as RSpec tests don't run concurrently
+class Fiber
+  def self.schedule(&block)
+    fiber = Fiber.new(blocking: true) do
+      Fiber.current.__set_result(block.call)
+    end
+    fiber.resume
+
+    fiber
+  end
+
+  def self.await(_)
+    # no-op
+  end
+end
+
+# define request helpers
+module RageRequestHelpers
+  include Rack::Test::Methods
+
+  alias_method :response, :last_response
+
+  APP = Rack::Builder.parse_file("#{Rage.root}/config.ru").yield_self do |app|
+    app.is_a?(Array) ? app[0] : app
+  end
+
+  def app
+    APP
+  end
+
+  %w(get options head).each do |method_name|
+    class_eval <<~RUBY, __FILE__, __LINE__ + 1
+      def #{method_name}(path, params: {}, headers: {})
+        request("#{method_name.upcase}", path, params: params, headers: headers)
+      end
+    RUBY
+  end
+
+  %w(post put patch delete).each do |method_name|
+    class_eval <<~RUBY, __FILE__, __LINE__ + 1
+      def #{method_name}(path, params: {}, headers: {}, as: nil)
+        if as == :json
+          params = params.to_json
+          headers["content-type"] = "application/json"
+        end
+
+        request("#{method_name.upcase}", path, params: params, headers: headers.merge("IODINE_HAS_BODY" => !params.empty?))
+      end
+    RUBY
+  end
+
+  def request(method, path, params: {}, headers: {})
+    if headers.any?
+      headers = headers.transform_keys do |k|
+        if k.downcase == "content-type"
+          "CONTENT_TYPE"
+        elsif k.downcase == "content-length"
+          "CONTENT_LENGTH"
+        elsif k.upcase == k
+          k
+        else
+          "HTTP_#{k.tr("-", "_").upcase! || k}"
+        end
+      end
+    end
+
+    custom_request(method, path, params, headers)
+  end
+
+  def host!(host)
+    @__host = host
+  end
+
+  def default_host
+    @__host || "example.org"
+  end
+end
+
+# include request helpers
+RSpec.configure do |config|
+  config.include(RageRequestHelpers, type: :request)
+end
+
+# patch MockResponse class
+class Rack::MockResponse
+  def parsed_body
+    if headers["content-type"].start_with?("application/json")
+      JSON.parse(body)
+    else
+      body
+    end
+  end
+
+  def code
+    status.to_s
+  end
+
+  alias_method :response_code, :status
+end
+
+# define http status matcher
+RSpec::Matchers.matcher :have_http_status do |expected|
+  codes = Rack::Utils::SYMBOL_TO_STATUS_CODE
+
+  failure_message do |response|
+    actual = response.status
+
+    if expected.is_a?(Integer)
+      "expected the response to have status code #{expected} but it was #{actual}"
+    elsif expected == :success
+      "expected the response to have a success status code (2xx) but it was #{actual}"
+    elsif expected == :error
+      "expected the response to have an error status code (5xx) but it was #{actual}"
+    elsif expected == :missing
+      "expected the response to have a missing status code (404) but it was #{actual}"
+    else
+      "expected the response to have status code :#{expected} (#{codes[expected]}) but it was :#{codes.key(actual)} (#{actual})"
+    end
+  end
+
+  failure_message_when_negated do |response|
+    actual = response.status
+
+    if expected.is_a?(Integer)
+      "expected the response not to have status code #{expected} but it was #{actual}"
+    elsif expected == :success
+      "expected the response not to have a success status code (2xx) but it was #{actual}"
+    elsif expected == :error
+      "expected the response not to have an error status code (5xx) but it was #{actual}"
+    elsif expected == :missing
+      "expected the response not to have a missing status code (404) but it was #{actual}"
+    else
+      "expected the response not to have status code :#{expected} (#{codes[expected]}) but it was :#{codes.key(actual)} (#{actual})"
+    end
+  end
+
+  match do |response|
+    actual = response.status
+
+    case expected
+    when :success
+      actual >= 200 && actual < 300
+    when :error
+      actual >= 500
+    when :missing
+      actual == 404
+    when Symbol
+      actual == codes.fetch(expected)
+    else
+      actual == expected
+    end
+  end
+end
+
+if defined? RSpec::Rails::Matchers
+  module RSpec::Rails::Matchers
+    def have_http_status(_)
+      super
+    end
+  end
+end
diff --git a/rage.gemspec b/rage.gemspec
index a368df05..794ca2ef 100644
--- a/rage.gemspec
+++ b/rage.gemspec
@@ -31,4 +31,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency "rack", "~> 2.0"
   spec.add_dependency "rage-iodine", "~> 3.0"
   spec.add_dependency "zeitwerk", "~> 2.6"
+  spec.add_dependency "rack-test", "~> 2.1"
 end
diff --git a/spec/rspec/config.ru b/spec/rspec/config.ru
new file mode 100644
index 00000000..f8774ed1
--- /dev/null
+++ b/spec/rspec/config.ru
@@ -0,0 +1,2 @@
+run Rage.application
+Rage.load_middlewares(self)
diff --git a/spec/rspec/config/application.rb b/spec/rspec/config/application.rb
new file mode 100644
index 00000000..5daddcbc
--- /dev/null
+++ b/spec/rspec/config/application.rb
@@ -0,0 +1 @@
+Rage.configure {}
diff --git a/spec/rspec/rspec_spec.rb b/spec/rspec/rspec_spec.rb
new file mode 100644
index 00000000..506d53a4
--- /dev/null
+++ b/spec/rspec/rspec_spec.rb
@@ -0,0 +1,134 @@
+module RspecHelpersSpec
+  class TestController < RageController::API
+    def index
+      render json: %w(test_1 test_2 test_3)
+    end
+
+    def params_action
+      render plain: params[:i]
+    end
+
+    def headers_action
+      if request.headers["Content-Type"] == "text/plain" &&
+        request.headers["Cache-Control"] == "max-age=604800, must-revalidate" &&
+        request.headers["Last-Modified"] == "Sun, 03 Sep 2017 00:17:02 GMT"
+        head :ok
+      else
+        head :bad_request
+      end
+    end
+
+    def fibers_action
+      i = 0
+
+      Fiber.await([
+        Fiber.schedule { i += 1 },
+        Fiber.schedule { i += 2 },
+      ])
+
+      render plain: i
+    end
+
+    def subdomain
+      head :ok
+    end
+  end
+
+  Rage.routes.draw do
+    root to: "rspec_helpers_spec/test#index"
+
+    get "params", to: "rspec_helpers_spec/test#params_action"
+    post "params", to: "rspec_helpers_spec/test#params_action"
+
+    get "headers", to: "rspec_helpers_spec/test#headers_action"
+    get "fibers", to: "rspec_helpers_spec/test#fibers_action"
+
+    get "subdomain", to: "rspec_helpers_spec/test#subdomain", constraints: { host: /rage-test/ }
+  end
+end
+
+RSpec.describe "RSpec helpers", type: :request do
+  before do
+    allow(Rage).to receive(:root).and_return(Pathname.new(__dir__).expand_path)
+    require "rage/rspec"
+  end
+
+  it "correctly parses responses" do
+    get "/"
+
+    expect(response.body).to eq('["test_1","test_2","test_3"]')
+    expect(response.parsed_body).to eq(%w(test_1 test_2 test_3))
+  end
+
+  it "correctly matches http statuses" do
+    get "/"
+
+    expect(response).to have_http_status(:ok)
+    expect(response).to have_http_status(200)
+
+    expect {
+      expect(response).to have_http_status(:missing)
+    }.to raise_error("expected the response to have a missing status code (404) but it was 200")
+
+    expect {
+      expect(response).to have_http_status(500)
+    }.to raise_error("expected the response to have status code 500 but it was 200")
+
+    expect {
+      expect(response).not_to have_http_status(:success)
+    }.to raise_error("expected the response not to have a success status code (2xx) but it was 200")
+  end
+
+  it "correctly passes params" do
+    get "/params?i=222"
+    expect(response.body).to eq("222")
+
+    post "/params?i=333"
+    expect(response.body).to eq("333")
+
+    post "/params", params: { i: "444" }
+    expect(response.body).to eq("444")
+
+    post "/params", params: { i: "555" }, as: :json
+    expect(response.body).to eq("555")
+  end
+
+  it "works correctly with no params" do
+    post "/params"
+    expect(response.body).to eq("")
+  end
+
+  it "correctly passes headers" do
+    get "/headers", headers: {
+      "content-type" => "text/plain",
+      "Cache-Control" => "max-age=604800, must-revalidate",
+      "HTTP_LAST_MODIFIED" => "Sun, 03 Sep 2017 00:17:02 GMT"
+    }
+
+    expect(response).to have_http_status(:ok)
+  end
+
+  it "allows to correctly schedule fibers" do
+    get "/fibers"
+    expect(response.body).to eq("3")
+  end
+
+  it "uses the default host value" do
+    get "/subdomain"
+    expect(response).to have_http_status(:not_found)
+  end
+
+  it "allows to modify host value" do
+    host! "rage-test.com"
+    get "/subdomain"
+
+    expect(response).to have_http_status(:ok)
+  end
+
+  it "allows to stub app calls" do
+    allow_any_instance_of(RageController::API).to receive(:params).and_return({ i: "12345" })
+
+    get "/params?i=111"
+    expect(response.body).to eq("12345")
+  end
+end