> This page is part of the [Customer.io documentation](https://docs.customer.io). For the complete index, see [llms.txt](https://docs.customer.io/llms.txt).
> Last updated: August 31, 2026
> To take actions in Customer.io from an agent, use the [Customer.io CLI](https://docs.customer.io/ai/cli/get-started.md) or the [MCP server](https://docs.customer.io/ai/mcp/get-started.md).

# Link an email to an automation

While you can [create a Design Studio email as a part of your automation, broadcast, or transactional message](/messaging/design-studio/file-manager/#create-from-an-automation), you can also [create the email first](/messaging/design-studio/emails/visual-editor/overview/) then link it to an automation later, as described in this article.

You can only link a Design Studio message to one automation.

You can link an email made in Design Studio to any automation, broadcast, or transactional message, but only one. If you’d like to link the same email to multiple automations, you can [duplicate the email](/messaging/design-studio/file-manager/#duplicate-files).

## Link your message

How you link your Design Studio message depends on the type of automation you’re working with.

### Automations and API-triggered broadcasts

1.  Open your automation or API-triggered broadcast.
2.  Drag an **Email** block into your workflow.
3.  Click **Add Content** in the email block.
4.  Under **Use a Design Studio Email**, hover over your email and click **Use email**. Your messages are displayed in order of how recently you edited them. (If you don’t see this option, click **Try it out!** in the top right to switch to Design Studio.)

You can link emails, not templates.

You can’t link templates to automations, but you can [create an email from a template](/messaging/design-studio/file-manager/#create-files). If you need to make a new email, click **Create in Design Studio** to get started.

### One-time sends and transactional messages

1.  Open your one-time send and go to the **Content** step.
2.  Choose **Email** as the message channel.
3.  Click the content block.
4.  Under **Use a Design Studio Email**, hover over your email and click **Use email**. Your messages are displayed in order of how recently you edited them. (If you don’t see this option, click **Try it out!** in the top right to switch to Design Studio.)

You can link emails, not templates.

You can’t link templates to automations, but you can [create an email from a template](/messaging/design-studio/file-manager/#create-files). If you need to make a new email, click **Create in Design Studio** to get started.

## Define the envelope

If you didn’t [fill out the envelope (From, To, etc)](/messaging/design-studio/emails/visual-editor/overview/#define-the-envelope) when creating the email, you can do so after you link the email too.

## Preview your message

Make sure you preview your liquid and test out your email with different accessibility settings:

*   Learn more about [adding and previewing liquid](/messaging/design-studio/emails/visual-editor/liquid-visual-editor/).
*   Learn more about [checking responsiveness, dark mode, and accessibility](/messaging/design-studio/emails/preview-email-in-design-studio/).
*   Learn more about [validating your code with our Developer Tools](/messaging/design-studio/emails/code-editor/developer-tools/) (you’ll have to switch to the code editor).

## A/B test your Design Studio message

You can A/B test your Design Studio message in a [automation](/messaging/send/workflows/a-b-test-automations/) or [one-time send](/messaging/send/broadcasts/one-time-sends/#testing-newsletter-broadcasts).

Each variation is a duplicate of the message you linked to your automation. Back in your Design Studio dashboard, all variations are grouped together under the original file name.

![Close up of three files in the Design Studio dashboard table. The top header is the name of a file with a flask icon. Indented under this header are two variants A and B.](https://docs.customer.io/images/design-studio-a-b-test.png)

The winning variant will have a trophy icon next to it.

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