# Testing emails with a local SMTP Server

> In this recipe, we extend and configure Makerkit to have a fully local email server to test our application's outgoing emails

*Published: 2022-10-08*
*Canonical: https://makerkit.dev/blog/tutorials/testing-emails-local-email-server*

---

Makerkit uses [Ethereal](https://ethereal.email) for email testing, a neat
service that catches all the email sent from the application.

Ethereal is an incredibly useful during development because it allows us to
freely test the emails sent while testing, especially if we're designing
pixel-perfect emails with MJML.

Another alternative is setting up a fully local SMTP server with [SMTP4Dev](https://github.com/rnwood/smtp4dev) and Docker. This can be preferable if
you prefer not to send data to an external service or if you need to work
offline.

Let's see how we can get it done!

## Running the Docker Instance

To run the SMTP4Dev Docker image, ensure you're running Docker, and then run
the following command:

```
docker run --rm -it -p 3300:80 -p 2525:25 rnwood/smtp4dev
```

We've initialized the HTTP server at [localhost:3300](localhost:3300), so go
ahead and give it a try!

## Configuring Makerkit

Now we have to add the correct configuration to and make a small adjustement
to the codebase.

As we've said, Makerkit uses Ethereal by default: we need to remove that.
Open the file at `src/core/email/send-email.ts` and delete the lines 22-24:

```
if (configuration.emulator) {
  return getEtherealMailTransporter();
}
```

Then, we update the configuration at `src/configuration.ts` with the
following email setup:

```ts
email: {
  host: '0.0.0.0',
  port: 2525,
  user: 'user',
  password: 'pass',
  senderAddress: 'test@makerkit.dev',
},
```

And that's pretty much it! To test that everything works, send an email
using the application by inviting a member from the Members page.

🎉 We now have a fully local email server to test our emails!