# Dependency Container Slim uses a dependency container to prepare, manage, and inject application dependencies. Slim supports containers that implement the [Container-Interop](https://github.com/container-interop/container-interop) interface. You can use Slim’s built-in container (based on [Pimple](http://pimple.sensiolabs.org/)) or third-party containers like [Acclimate](https://github.com/jeremeamia/acclimate-container) or [PHP-DI](http://php-di.org/). ## How to use the container You don’t *have* to provide a dependency container. If you do, however, you must inject the container instance into the Slim application’s constructor. ~~~ $container = new \Slim\Container; $app = new \Slim\App($container); ~~~ You can fetch services from your container explicitly or implicitly. You can fetch an explicit reference to the container instance from inside a Slim application route like this: ~~~ /** * Example GET route * * @param \Psr\Http\Message\ServerRequestInterface $req PSR7 request * @param \Psr\Http\Message\ResponseInterface $res PSR7 response * @param array $args Route parameters * * @return \Psr\Http\Message\ResponseInterface */ $app->get('/foo', function ($req, $res, $args) { $container = $this->getContainer(); $myService = $container->get('myService'); return $res; }); ~~~ You can implicitly fetch services from the container like this: ~~~ /** * Example GET route * * @param \Psr\Http\Message\ServerRequestInterface $req PSR7 request * @param \Psr\Http\Message\ResponseInterface $res PSR7 response * @param array $args Route parameters * * @return \Psr\Http\Message\ResponseInterface */ $app->get('/foo', function ($req, $res, $args) { $myService = $this->myService; return $res; }); ~~~ Slim uses `__get()` and `__isset()` magic methods that defer to the application’s container for all properties that do not already exist on the application instance. ## Required services Your container MUST implement these required services. If you use Slim’s built-in container, these are provided for you. If you choose a third-party container, you must define these required services on your own. ### settings Associative array of application settings, including keys `httpVersion`, `outputBuffering`,`responseChunkSize` and `determineRouteBeforeAppMiddleware`. ### environment Instance of `\Slim\Interfaces\Http\EnvironmentInterface`. ### request Instance of `\Psr\Http\Message\ServerRequestInterface`. ### response Instance of `\Psr\Http\Message\ResponseInterface`. ### router Instance of `\Slim\Interfaces\RouterInterface`. ### foundHandler Instance of `\Slim\Interfaces\InvocationStrategyInterface`. ### errorHandler Callable invoked if application error. The callable MUST return an instance of`\Psr\Http\Message\ResponseInterface` and accept three arguments: 1. `\Psr\Http\Message\ServerRequestInterface` 2. `\Psr\Http\Message\ResponseInterface` 3. `\Exception` ### notFoundHandler Callable invoked if the current HTTP request URI does not match an application route. The callable MUST return an instance of `\Psr\Http\Message\ResponseInterface` and accept two arguments: 1. `\Psr\Http\Message\ServerRequestInterface` 2. `\Psr\Http\Message\ResponseInterface` ### notAllowedHandler Callable invoked if an application route matches the current HTTP request path but not its method. The callable MUST return an instance of `\Psr\Http\Message\ResponseInterface`and accept three arguments: 1. `\Psr\Http\Message\ServerRequestInterface` 2. `\Psr\Http\Message\ResponseInterface` 3. Array of allowed HTTP methods