# Configuring Capsul-Flask

Create a `.env` file to set up the application configuration:

```
nano .env
```

You can enter any environment variables referenced in `__init__.py` to this file.

For example you may enter your SMTP credentials like this:
```
MAIL_USERNAME=forest@nullhex.com
MAIL_DEFAULT_SENDER=forest@nullhex.com
MAIL_PASSWORD=**************
```

## Loading variables from files

To support [Docker Secrets](https://docs.docker.com/engine/swarm/secrets/), you can also load secret values from files – for example, to load `MAIL_PASSWORD` from `/run/secrets/mail_password`, set
```sh
MAIL_PASSWORD_FILE=/run/secrets/mail_password
```