How to Send a Klaviyo Test Email and Preview It Across Devices

Klaviyo's editor can preview a campaign or flow email while you work. A delivered-email preview adds a different check: it shows the test message after Klaviyo has assembled and sent it, then captures that same email in Gmail, Outlook, Apple Mail, iPhone, Android, and other selected clients.

This guide shows how to send a Klaviyo test email to a MailSlurp render address and inspect the completed screenshots. It is useful for campaigns, flows, dynamic product blocks, responsive layouts, hosted images, tracked links, footers, light mode, and dark mode.

For the product overview and supported client families, open the Klaviyo email preview page.

Quick answer

To send and preview a Klaviyo test email:

1. Open the finished email in Klaviyo and click Preview.
2. Find Send a preview using a profile in the Preview panel.
3. Open Device Previews in MailSlurp and start a new render.
4. Select the clients you need, then copy the render address.
5. Paste that address into Klaviyo and click Send test.
6. Confirm that Klaviyo reports a successful test send.
7. Return to MailSlurp and open the detected email results.
8. Wait for the required client captures to complete.
9. Review the Gmail, Outlook, iPhone, Android, and desktop screenshots.

Use the version closest to launch. Finish the copy, images, links, tracking, personalization, footer, and unsubscribe content before sending the approval test.

Watch the Klaviyo email preview workflow

This walkthrough shows the full process: create a MailSlurp render, send the Klaviyo test email to its address, and inspect the completed Gmail, Outlook, iPhone, Android, and desktop previews.

Step 1: Open Preview in Klaviyo

Open the campaign, template, or flow email you want to test. In the editor shown here, click Preview in the upper-right corner.

Klaviyo's desktop and mobile editor views are useful for fast design checks. Keep the email on the final content version so the delivered test matches the message under review.

Step 2: Find the test-send controls

In Preview mode, stay on the Preview tab and find Send a preview using a profile. This area lets you choose representative profile data and send the assembled email to a test address.

Klaviyo also provides a separate Inbox testing tab for paid accounts. The workflow below uses Klaviyo's test-send field so MailSlurp can receive the delivered email and keep the selected device screenshots together.

See Klaviyo's current inbox testing instructions if you also want to compare the in-platform workflow.

Step 3: Start a MailSlurp device render

Open Device Previews in MailSlurp and click Start new render.

This creates a render workflow with a dedicated address that Klaviyo can use as the test recipient.

Step 4: Choose clients and copy the render address

Select the desktop, web, mobile, tablet, light-mode, and dark-mode clients that represent your audience. Then copy the address under Send your email to this address.

A practical Klaviyo campaign check usually includes Gmail, Outlook, Apple Mail, iOS, Android, and the dark-mode variants that matter for the template.

Step 5: Send the Klaviyo test email to MailSlurp

Return to Klaviyo. Paste the complete MailSlurp render address into the preview-recipient field, choose any profile data required by the template, and click Send test.

Use realistic profile or event data when personalization changes layout. Long names, missing optional values, discount codes, product images, and repeated order rows can all alter the final render.

Step 6: Confirm that Klaviyo sent the test

Wait for the green Your test message sent successfully confirmation before returning to MailSlurp.

If the confirmation does not appear, check the recipient address and any Klaviyo test-send limits before trying again.

Step 7: Open the detected email results

MailSlurp detects the incoming Klaviyo message and creates a run automatically. Click View results when the waiting dialog shows the email.

If the email does not appear, copy the entire render address again and confirm that the successful Klaviyo test used that exact recipient.

Step 8: Wait for the required renders

Each selected client is captured separately. The progress summary shows how many screenshots are ready, still capturing, or failed.

You can begin reviewing completed targets while slower clients finish. Do not treat a still-capturing result as a missing preview.

Step 9: Review Gmail, iPhone, and Outlook previews

Scan the completed grid first, then open any client that needs closer inspection. Compare the same delivered Klaviyo email across webmail, native mobile apps, and desktop clients.

Check the details most likely to affect a customer:

• images that are missing, clipped, stretched, or slow to load
• headings or product rows that wrap differently
• columns that do not stack cleanly on mobile
• buttons that disappear or become difficult to tap
• logos, text, and backgrounds with poor dark-mode contrast
• Outlook spacing, font, table, or width changes
• footer, unsubscribe, preference, and tracked links

Use Compare when two clients show different behavior. Rerun the preview after the last template change so approval always refers to the current Klaviyo send.

Klaviyo preview and inbox testing checklist

Before scheduling the campaign or enabling the flow, confirm:

• the intended Klaviyo profile or event data was used
• the complete test message arrived at the MailSlurp render address
• priority web, desktop, mobile, and dark-mode captures are complete
• images, headings, product blocks, and buttons fit at each width
• footer, unsubscribe, preference, and tracked links are present
• Gmail, Outlook, and iPhone results have been inspected closely
• the final result was rerun after the last content or template edit

For a repeatable team process, continue with the email preview approval workflow and the email rendering QA checklist.

Troubleshooting Klaviyo device previews

The test email does not arrive in MailSlurp

• Copy the complete render address again.
• Confirm that Klaviyo showed the successful test-send message.
• Check whether the Klaviyo account has reached a preview-send limit.
• Make sure the recipient field does not contain an old test address.

Personalization does not match the intended recipient

Choose the correct Klaviyo profile or event before sending the preview. If the email depends on live campaign behavior, use a controlled test profile or preview segment that contains the required data.

Images are missing in one or more clients

• Use absolute HTTPS image URLs.
• Confirm that each image is publicly reachable without authentication.
• Check that the latest image version was saved in Klaviyo.
• Compare the failing client with another completed render before changing the template.

One result is still capturing

Wait for the required client to finish, then refresh if necessary. Other completed targets remain available for review while one result is still running.

FAQ

How do I send a test email in Klaviyo?

Open the email editor, click Preview, find Send a preview using a profile, enter the test recipient, and click Send test. For cross-client review, use a MailSlurp render address as that recipient.

Can I preview a Klaviyo email in Gmail and Outlook?

Yes. Send the Klaviyo test email to a MailSlurp render address, then select the Gmail, Outlook, Apple Mail, iPhone, Android, desktop, light-mode, and dark-mode targets you need.

Is Klaviyo Inbox testing the same as sending a preview email?

No. Klaviyo exposes Inbox testing as a separate paid-account workflow. Sending a preview email uses the test-recipient field. This guide sends that delivered preview to MailSlurp for a reusable cross-client result.

Does MailSlurp use the email Klaviyo actually sent?

Yes. MailSlurp receives the Klaviyo test message and renders that delivered email, including the HTML, hosted images, links, footer, and content present in the test send.

When should I rerun the preview?

Rerun it after changing copy, images, product blocks, personalization, layout, links, tracking, footer content, or campaign settings. Final approval should always refer to the latest delivered version.

Create a MailSlurp account to get started for free with device renders included each month.