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One template renders differently in every inbox it reaches. Device Preview runs it on the clients you pick and screenshots each one. Not a simulation of Outlook. Outlook itself, on Windows, opening your message.
A Device Preview run showing one email rendered on Apple Mail, Gmail, and Outlook, in light and dark mode

A Device Preview run across desktop, mobile, and webmail clients

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Run a preview

Open a template in and click the device icon in the toolbar. Previews render whatever is in the editor right now, including unpublished changes. Choose a target set, the group of clients you want to render on. Every workspace starts with Courier Recommended, an 8-client set spanning desktop, mobile, and webmail in both light and dark mode. Build your own from the full catalog. If your template is , choose which translation to render. Set test values for any variables, such as profile.name.
Variables left empty render as written, so {{profile.name}} appears literally in the screenshot. That is the most common reason a preview looks broken when the template is fine.
Click Run preview. Screenshots load as they return, and a full run takes 10 to 60 seconds depending on how many clients you picked.

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Review the results

Click a screenshot to open it full size, then use the arrows to move through the run. Each one shows the full inbox view, so you can check the subject line and sender name along with the email body. Download any screenshot from the results page.

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Find past runs

Click Preview history for past runs. Each shows when it ran, how many clients it covered, and which template version was live at the time. That last part is the useful one. It tells you whether a rendering problem is new or shipped several versions ago. Runs are kept for one year.

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Build a target set

Create your own target sets to focus on the variations you care about. You might keep one for Outlook versions, another for dark mode across mobile, and a third for the clients most of your users are on. Open the Targets dropdown and click Create new set. Name it, filter the catalog by Mobile, Web, or Application, then add the clients you want. Use the pencil icon to edit a set later. Sets are shared with your workspace and scoped to the you are in.

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Pricing

Device Preview is a paid monthly add-on. Enable it in the console under Settings → Billing. Each plan includes a set number of previews per month, and anything beyond that is billed per preview. Included previews reset each month and do not roll over.

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Supported clients

A client is one combination of app, device, OS, browser, and colour mode. The catalog below is the current set, and new devices and OS versions are added over time.

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Desktop applications

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Mobile applications

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Webmail

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Limits & behavior

  • Previews render the editor, not the published version. Unpublished changes are included, so a preview can show content no recipient has received.
  • Runs are kept for one year. Preview history records the template version that was live at the time.
  • Target sets are per environment. A set built in Test is not available in Production.
  • The catalog changes. Devices and OS versions are added over time, so a saved target set may cover more clients later than it did when you built it.