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Inbox previews in Brew, rendered per client from a chat prompt
An email that looks perfect on the canvas can still break in a real inbox. Outlook mangles a table, dark mode inverts your logo, a mobile client squeezes a two-column layout. Brew renders your design across real email clients and devices and returns a screenshot per client. That way you catch rendering issues before the send goes out. This works for any design, one-off Emails and automation emails alike.

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Run a Preview

1

Open a design on the canvas

Open any email. In the Preview panel on the right, switch to the Inboxes tab.
2

Pick your clients

Choose the default spread (Gmail, Outlook, Apple Mail, and iOS) or select specific clients, including OS, version, and light/dark mode combinations.
3

Review the results

Screenshots come back per client. Clients that are slow to render show as Pending. Click Retry to fetch just those without re-running the rest.
Each preview run costs a fixed number of credits, charged only when at least one client actually renders. If nothing comes back, you aren’t billed.

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Supported Clients

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What to Check

  • Outlook first. Outlook on Windows uses its own rendering engine and is the most common place layouts break. Check tables, spacing, and background images there before anywhere else.
  • Dark mode. iOS and Apple Mail dark variants show whether your colors invert gracefully. Watch for logos that vanish on dark backgrounds and text that loses contrast.
  • Mobile. The iOS and Android variants confirm your layout stacks correctly on a narrow screen.

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Inbox Previews vs Test Sends

Both have a place in your pre-send routine:
  • Inbox previews show how the design renders across many clients at once, no inbox accounts needed, results in one grid.
  • Test sends deliver the real email to your own address, so you can check the from name, subject, preview text, and links as an actual recipient.
A good habit: preview across inboxes while iterating, then send yourself a test right before the real send.

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From the API

The same feature is available programmatically:
  • API: POST /v1/emails/{emailId}/client-previews. Pass clients with ids from the supported catalogue, or an empty body for the default spread. It starts a rendering job and returns its previewId; poll GET /v1/emails/client-previews/{previewId} until the job finishes.
  • TypeScript SDK: brew.emails.previewClients({ emailId }) starts the job; poll brew.emails.getClientPreview(previewId).
  • MCP: the test_email_rendering tool, so agents can QA a design as part of a workflow. It returns a previewId right away, and the agent polls get_email_rendering with it until the screenshots are ready. Ask for a preview in chat and the screenshots come back in the conversation, with a link to each full-size render. For a free look at the design itself, get_email returns its preview.
Claude running a Brew inbox preview over MCP, returning Apple Mail and Gmail renders
See the API Reference for the full client catalogue and response shape.

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Need Help?

Our team is ready to support you at every step of your journey with Brew. Choose the option that works best for you:

Search Documentation

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ChatGPT/Claude Integration

Click “Open in ChatGPT” at the top right of any page to explore it further with ChatGPT or Claude.