diff --git a/VERSION b/VERSION
index 7beab95..4109faf 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.2301.50234
+0.2301.62020
diff --git a/src/Http/HttpFx.php b/src/Http/HttpFx.php
index 7ea25a3..c6bf3da 100644
--- a/src/Http/HttpFx.php
+++ b/src/Http/HttpFx.php
@@ -1,7 +1,7 @@
 <?php
 // HttpFx.php
 // Created: 2022-02-15
-// Updated: 2022-02-27
+// Updated: 2023-01-06
 
 namespace Index\Http;
 
@@ -16,12 +16,13 @@ use Index\Http\Content\BencodedContent;
 use Index\Http\Content\JsonContent;
 use Index\Http\Content\StreamContent;
 use Index\Http\Content\StringContent;
+use Index\Routing\IRouter;
 use Index\Routing\Router;
 use Index\Routing\RoutePathNotFoundException;
 use Index\Routing\RouteMethodNotSupportedException;
 use Index\Serialisation\IBencodeSerialisable;
 
-class HttpFx {
+class HttpFx implements IRouter {
     private Router $router;
     private array $objectHandlers = [];
     private array $errorHandlers = [];
diff --git a/src/Routing/IRouter.php b/src/Routing/IRouter.php
new file mode 100644
index 0000000..1693847
--- /dev/null
+++ b/src/Routing/IRouter.php
@@ -0,0 +1,81 @@
+<?php
+// IRouter.php
+// Created: 2023-01-06
+// Updated: 2023-01-06
+
+namespace Index\Routing;
+
+interface IRouter {
+    /**
+     * Apply middleware functions to a path.
+     *
+     * @param string $path Path to apply the middleware to.
+     * @param callable $handler Middleware function.
+     */
+    public function use(string $path, callable $handler): void;
+
+    /**
+     * Merges another router with this one with possibility of changing its root.
+     *
+     * @param string $path Base path to use.
+     * @param Router $router Router object to inherit from.
+     */
+    public function merge(string $path, Router $router): void;
+
+    /**
+     * Adds a new route.
+     *
+     * @param string $method Request method.
+     * @param string $path Request path.
+     * @param callable $handler Request handler.
+     */
+    public function add(string $method, string $path, callable $handler): void;
+
+    /**
+     * Adds a new GET route.
+     *
+     * @param string $path Request path.
+     * @param callable $handler Request handler.
+     */
+    public function get(string $path, callable $handler): void;
+
+    /**
+     * Adds a new POST route.
+     *
+     * @param string $path Request path.
+     * @param callable $handler Request handler.
+     */
+    public function post(string $path, callable $handler): void;
+
+    /**
+     * Adds a new DELETE route.
+     *
+     * @param string $path Request path.
+     * @param callable $handler Request handler.
+     */
+    public function delete(string $path, callable $handler): void;
+
+    /**
+     * Adds a new PATCH route.
+     *
+     * @param string $path Request path.
+     * @param callable $handler Request handler.
+     */
+    public function patch(string $path, callable $handler): void;
+
+    /**
+     * Adds a new PUT route.
+     *
+     * @param string $path Request path.
+     * @param callable $handler Request handler.
+     */
+    public function put(string $path, callable $handler): void;
+
+    /**
+     * Adds a new OPTIONS route.
+     *
+     * @param string $path Request path.
+     * @param callable $handler Request handler.
+     */
+    public function options(string $path, callable $handler): void;
+}
diff --git a/src/Routing/Router.php b/src/Routing/Router.php
index f5d89ef..bb5f78f 100644
--- a/src/Routing/Router.php
+++ b/src/Routing/Router.php
@@ -1,7 +1,7 @@
 <?php
 // Router.php
 // Created: 2022-01-18
-// Updated: 2022-02-27
+// Updated: 2023-01-06
 
 namespace Index\Routing;
 
@@ -10,7 +10,7 @@ use InvalidArgumentException;
 /**
  * Provides an application router.
  */
-class Router {
+class Router implements IRouter {
     private RouteInfo $route;
 
     /**