# Transactional Emails (/concepts/transactional-emails)

Transactional emails are emails sent directly through the API. They are typically used for one-to-one communication, such as password resets, order confirmations, and notifications.

## Sending with attachments

Plunk supports sending attachments with transactional emails. By default, you can include up to 10 attachments per email with a maximum total size of 10MB. Attachments should be base64 encoded and included in the `attachments` array when sending the email via the [/v1/email/send](/api-reference/public-api/sendEmail) endpoint.

Self-hosters can raise these limits via environment variables to match the capacity of the underlying email provider (AWS SES supports up to 40MB per message by default):

| Variable                 | Default | Description                                |
| ------------------------ | ------- | ------------------------------------------ |
| `MAX_ATTACHMENT_SIZE_MB` | `10`    | Maximum total attachment size in megabytes |
| `MAX_ATTACHMENTS_COUNT`  | `10`    | Maximum number of attachments per email    |

## Sending from a template

You can also send transactional emails using a [template](/concepts/templates) you have created in the dashboard. This allows you to reuse the same design and content for multiple emails, while still personalizing them with contact data.