diff --git a/CHANGELOG.md b/CHANGELOG.md
index dfb5e9dc..b7b9aa56 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@ All notable changes to `Slytherin` will be documented in this file.
 
 ## [0.9.7](https://github.com/rougin/slytherin/compare/v0.9.6...master) - Unreleased
 
+### Added
+- `preferred` property in `HttpIntegration`, `RoutingIntegration` for specifying third-party integrations
+
 ### Fixed
 - Type hinting of all classes using `PHPStan`
 
diff --git a/src/Http/HttpIntegration.php b/src/Http/HttpIntegration.php
index 63984849..42c50995 100644
--- a/src/Http/HttpIntegration.php
+++ b/src/Http/HttpIntegration.php
@@ -22,6 +22,11 @@
  */
 class HttpIntegration implements IntegrationInterface
 {
+    /**
+     * @var string|null
+     */
+    protected $preferred = null;
+
     /**
      * Defines the specified integration.
      *
@@ -119,7 +124,13 @@ protected function headers(array $server)
      */
     protected function resolve(ContainerInterface $container, ServerRequestInterface $request, ResponseInterface $response)
     {
-        if (class_exists('Zend\Diactoros\ServerRequestFactory'))
+        $empty = $this->preferred === null;
+
+        $hasDiactoros = class_exists('Zend\Diactoros\ServerRequestFactory');
+
+        $wantDiactoros = $this->preferred === 'diactoros';
+
+        if (($empty || $wantDiactoros) && $hasDiactoros)
         {
             $response = new ZendResponse;
 
diff --git a/src/Routing/RoutingIntegration.php b/src/Routing/RoutingIntegration.php
index f63656a4..383021db 100644
--- a/src/Routing/RoutingIntegration.php
+++ b/src/Routing/RoutingIntegration.php
@@ -16,6 +16,11 @@
  */
 class RoutingIntegration implements IntegrationInterface
 {
+    /**
+     * @var string|null
+     */
+    protected $preferred = null;
+
     /**
      * Defines the specified integration.
      *
@@ -25,15 +30,27 @@ class RoutingIntegration implements IntegrationInterface
      */
     public function define(ContainerInterface $container, Configuration $config)
     {
+        $hasFastroute = interface_exists('FastRoute\Dispatcher');
+
+        $wantFastroute = $this->preferred === 'fastroute';
+
+        $hasPhroute = class_exists('Phroute\Phroute\Dispatcher');
+
+        $wantPhroute = $this->preferred === 'phroute';
+
         $dispatcher = new Dispatcher;
 
         $router = $config->get('app.router', new Router);
 
-        if (interface_exists('FastRoute\Dispatcher')) {
+        $empty = $this->preferred === null;
+
+        if (($empty || $wantFastroute) && $hasFastroute)
+        {
             $dispatcher = new FastRouteDispatcher;
         }
 
-        if (class_exists('Phroute\Phroute\Dispatcher')) {
+        if (($empty || $wantPhroute) && $hasPhroute)
+        {
             $resolver = new PhrouteResolver($container);
 
             $dispatcher = new PhrouteDispatcher(null, $resolver);