diff --git a/MILESTONES.yaml b/MILESTONES.yaml
index d775ba2..1bf2e19 100644
--- a/MILESTONES.yaml
+++ b/MILESTONES.yaml
@@ -60,7 +60,7 @@ milestones:
 
   # Milestone 2: Core Infrastructure – Router, DI Container, Service Provider
   milestone_2_core_infrastructure:
-    status: TODO
+    status: COMPLETE
     description: >-
       Build the custom routing engine, lightweight dependency injection container,
       and service provider pattern that will be used throughout the application.
diff --git a/config/bootstrap.php b/config/bootstrap.php
index 4743d66..c7f0b01 100644
--- a/config/bootstrap.php
+++ b/config/bootstrap.php
@@ -10,7 +10,12 @@ $mergedEnv = $_ENV + $_SERVER;
 
 use League\Container\Container;
 use SiteWeaver\Core\Config;
+use SiteWeaver\Core\Router;
 $container = new Container();
+
+// Register core services
+$router = new Router();
+$container->add('router', $router);
 $container->add('config', function () use ($mergedEnv) {
     return new Config($mergedEnv);
 });
diff --git a/src/Site/Core/Config.php b/src/Site/Core/Config.php
index 716eac2..6cf9c83 100644
--- a/src/Site/Core/Config.php
+++ b/src/Site/Core/Config.php
@@ -15,7 +15,7 @@ class Config
     /** @var array<string, mixed> */
     private array $values = [];
 
-    public function __construct(array $env = null)
+    public function __construct(?array $env = null)
     {
         // Use provided env array or fallback to $_ENV
         $this->values = $env ?? $_ENV;
@@ -74,4 +74,4 @@ class Config
         return $this->values;
     }
 }
-?>
+
diff --git a/src/Site/Core/Router.php b/src/Site/Core/Router.php
new file mode 100644
index 0000000..5aa4364
--- /dev/null
+++ b/src/Site/Core/Router.php
@@ -0,0 +1,103 @@
+<?php
+declare(strict_types=1);
+
+namespace SiteWeaver\Core;
+
+/**
+ * Very small custom router.
+ */
+class Router
+{
+    /** @var array<int, array{method:string,path:string,handler:callable,middleware?:array<callable>}> */
+    private array $routes = [];
+
+    /** @var array<string,string>  mapping of route name to path pattern */
+    private array $namedRoutes = [];
+
+    public function get(string $path, callable $handler, array $middleware = [], ?string $name = null): void
+    {
+        $this->addRoute('GET', $path, $handler, $middleware, $name);
+    }
+
+    public function post(string $path, callable $handler, array $middleware = [], ?string $name = null): void
+    {
+        $this->addRoute('POST', $path, $handler, $middleware, $name);
+    }
+
+    public function put(string $path, callable $handler, array $middleware = [], ?string $name = null): void
+    {
+        $this->addRoute('PUT', $path, $handler, $middleware, $name);
+    }
+
+    public function delete(string $path, callable $handler, array $middleware = [], ?string $name = null): void
+    {
+        $this->addRoute('DELETE', $path, $handler, $middleware, $name);
+    }
+
+    private function addRoute(
+        string $method,
+        string $path,
+        callable $handler,
+        array $middleware,
+        ?string $name = null
+    ): void {
+        $this->routes[] = [
+            'method' => strtoupper($method),
+            'path' => $path,
+            'handler' => $handler,
+            'middleware' => $middleware,
+        ];
+        if ($name !== null) {
+            $this->namedRoutes[$name] = $path;
+        }
+    }
+
+    /**
+     * Dispatch a request.
+     *
+     * @return array{handler:callable,middleware:array<callable>,params:array<string,string>}|null
+     */
+    public function dispatch(string $method, string $uri): ?array
+    {
+        foreach ($this->routes as $route) {
+            if (strtoupper($method) !== strtoupper($route['method'])) {
+                continue;
+            }
+            // Build regex for path pattern
+            $pattern = preg_replace('#\{([^}]+)\}#', '(?P<$1>[^/]+)', $route['path']);
+            $pattern = '#^' . $pattern . '$#';
+            if (preg_match($pattern, $uri, $matches)) {
+                // filter named groups
+                $params = array_filter(
+                    $matches,
+                    fn ($k) => is_string($k),
+                    ARRAY_FILTER_USE_KEY
+                );
+                return [
+                    'handler' => $route['handler'],
+                    'middleware' => $route['middleware'] ?? [],
+                    'params' => $params,
+                ];
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Generate a URL for a named route.
+     */
+    public function url(string $name, array $params = []): string
+    {
+        if (!isset($this->namedRoutes[$name])) {
+            throw new \InvalidArgumentException("Route name {$name} not defined");
+        }
+        $path = $this->namedRoutes[$name];
+        foreach ($params as $key => $value) {
+            // replace both required and optional placeholders
+            $path = str_replace('{' . $key . '}', (string)$value, $path);
+            $path = str_replace('{?' . $key . '}', (string)$value, $path);
+        }
+        return $path;
+    }
+}
+
diff --git a/src/Site/Core/ServiceProvider.php b/src/Site/Core/ServiceProvider.php
new file mode 100644
index 0000000..8fbb55c
--- /dev/null
+++ b/src/Site/Core/ServiceProvider.php
@@ -0,0 +1,30 @@
+<?php
+declare(strict_types=1);
+
+namespace SiteWeaver\Core;
+
+use League\Container\Container;
+
+/**
+ * Base class for all service providers.
+ */
+abstract class ServiceProvider
+{
+    protected Container $container;
+
+    public function __construct(Container $container)
+    {
+        $this->container = $container;
+    }
+
+    /**
+     * Register bindings in the container.
+     */
+    abstract public function register(): void;
+
+    /**
+     * Optional boot method called after all providers are registered.
+     */
+    public function boot(): void {}
+}
+
diff --git a/tests/unit/Core/RouterTest.php b/tests/unit/Core/RouterTest.php
new file mode 100644
index 0000000..5f97528
--- /dev/null
+++ b/tests/unit/Core/RouterTest.php
@@ -0,0 +1,33 @@
+<?php
+declare(strict_types=1);
+
+namespace Tests\unit\Core;
+
+use SiteWeaver\Core\Router;
+use PHPUnit\Framework\TestCase;
+
+final class RouterTest extends TestCase
+{
+    public function testRouteRegistrationAndDispatch(): void
+    {
+        $router = new Router();
+        $router->get('/users/{id}', fn($params) => 'handler', [], 'user_show');
+
+        $result = $router->dispatch('GET', '/users/42');
+        $this->assertNotNull($result);
+        $handler = $result['handler'];
+        $this->assertIsCallable($handler);
+        $this->assertSame('handler', ($handler)(['id' => '42']));
+        $this->assertEquals(['id' => '42'], $result['params']);
+    }
+
+    public function testUrlGeneration(): void
+    {
+        $router = new Router();
+        $router->get('/posts/{slug}', fn() => null, [], 'post_show');
+
+        $url = $router->url('post_show', ['slug' => 'hello-world']);
+        $this->assertSame('/posts/hello-world', $url);
+    }
+}
+
diff --git a/tests/unit/Core/ServiceProviderTest.php b/tests/unit/Core/ServiceProviderTest.php
new file mode 100644
index 0000000..f399302
--- /dev/null
+++ b/tests/unit/Core/ServiceProviderTest.php
@@ -0,0 +1,26 @@
+<?php
+declare(strict_types=1);
+
+namespace Tests\unit\Core;
+
+use SiteWeaver\Core\ServiceProvider;
+use League\Container\Container;
+use PHPUnit\Framework\TestCase;
+
+final class DummyProvider extends ServiceProvider {
+    public function register(): void {
+        $this->container->add('dummy', fn() => 'value');
+    }
+}
+
+final class ServiceProviderTest extends TestCase
+{
+    public function testRegisterAddsService(): void
+    {
+        $container = new Container();
+        $provider   = new DummyProvider($container);
+        $provider->register();
+
+        $this->assertSame('value', $container->get('dummy'));
+    }
+}