# Rendering and sending emails

In the previous versions of Dotkernel API we have been composing email bodies using **Twig** from the `mezzio/mezzio-twigrenderer` package.
In the current version of Dotkernel API, we introduced the core mail service `Core/src/App/src/Service/MailService` which is responsible for sending all emails.

Being a core service, `MailService` is used across all projects implementing the Core architecture.
To compose and send an email, a solid implementation of `TemplateRendererInterface` was required to be injected into `MailService`, because each method rendered and parsed their respective templates in place before sending an email.
This is acceptable with other Dotkernel applications which in most cases return a rendered template, but being that Dotkernel API mostly returns JSON objects, rendered with a different renderer, **Twig** had to be replaced with a lighter solution.

The solution is a custom [`Api\App\Template\Renderer`](https://github.com/dotkernel/api/blob/6.0/src/App/src/Template/Renderer.php) implementing [`Api\App\Template\RendererInterface`](https://github.com/dotkernel/api/blob/6.0/src/App/src/Template/RendererInterface.php).
This is a lightweight renderer, aimed at rendering a combination of **PHP** and **HTML** files with `phtml` extension.

With the new solution, `MailService` requires no implementation of any renderer because it no longer has to render templates internally.
Instead, an implementation of `Api\App\Template\RendererInterface` is first injected in the handler:

```php
class ExampleHandler extends AbstractHandler
{
    #[Inject(
        MailService::class,
        RendererInterface::class,
    )]
    public function __construct(
        protected MailService $mailService,
        protected RendererInterface $renderer,
    ) {
}
```

Then, the handler calls the renderer and saves the rendered template in a variable:

```php
$body = $this->renderer->render('user::welcome', ['user' => $user]);
```

And finally, the handler calls the mail service with the composed $body being passed as a parameter to the method which sends the email:

```php
// $user object contains email, firstname and lastname

$this->mailService->sendWelcomeMail($user, $body);
```

> Other Dotkernel applications implementing the Core architecture do the same in the handlers, but keep using Twig as the template renderer.