A Kit email preview should show the campaign after it leaves the editor. MailSlurp receives the actual Kit test email and renders that delivered message across Gmail, Outlook, Apple Mail, Yahoo, iPhone, iPad, Android, and desktop clients. This gives campaign reviewers concrete evidence for responsive layout, image loading, buttons, typography, footers, and dark mode before launch. ## Quick answer To test a Kit email across clients and devices: 1. Open **Device Previews** in MailSlurp and create a render. 2. Select the Gmail, Outlook, Apple Mail, iPhone, Android, and dark-mode targets that matter to your audience. 3. Copy the complete MailSlurp render address. 4. In Kit, open the Broadcast editor and choose the preview or test-email action. 5. Enter the render address and send the test email. 6. Return to MailSlurp and wait until every selected target is **Ready**. 7. Compare the screenshots and correct the campaign before launch. Use the final sender, subject, preview text, body, images, links, personalization, footer, and unsubscribe content for the run. {{LANDING_SHORTCODE:POST_CTA_BANNER:%7B%22title%22%3A%22Preview%20your%20next%20Kit%20campaign%20before%20launch%22%2C%22content%22%3A%22Send%20the%20delivered%20Kit%20test%20email%20to%20MailSlurp%2C%20then%20review%20the%20exact%20layout%20across%20the%20inbox%20clients%20and%20devices%20your%20customers%20use.%22%2C%22buttonHref%22%3A%22https%3A%2F%2Fapp.mailslurp.com%2Fsign-up%2F%3FonboardingRequest%3DdevicePreview%22%2C%22buttonText%22%3A%22Start%20a%20device%20preview%22%2C%22buttonTheme%22%3A%22blue%22%2C%22image%22%3A%22%2Fassets%2Fhome%2Fdevice-render-devices.png%22%2C%22imageAlt%22%3A%22Email%20preview%20results%20across%20mobile%20and%20desktop%20clients%22%2C%22imageWidth%22%3A%22800%22%2C%22imageHeight%22%3A%22415%22%2C%22imagePosition%22%3A%22%22%7D}} ## Before you begin Configure Kit's required mailing address and verified sending address, then use a dedicated tag containing only controlled MailSlurp seeds. Finish the campaign before testing. If the email uses personalization, select a representative profile or contact so fallback content, conditional sections, and merge fields can be reviewed in the delivered message. ### How the Kit test path works Kit calls one-off email campaigns Broadcasts. Its editor can preview content as a selected subscriber or send a test email; the MailSlurp render address belongs in the test-email path, while representative subscriber data should be chosen separately for personalization review. See the [Kit Broadcast documentation](https://help.kit.com/en/articles/2934648-creating-sending-and-publishing-broadcasts) for the provider's current account and campaign requirements. ## Step 1: Create a MailSlurp device preview Open [Device Previews](https://app.mailslurp.com/device-previews) and create a new render. Select a target set that represents your audience. A practical release check includes Gmail web and dark mode, Outlook.com, New Outlook, Outlook Classic, Apple Mail, iOS Mail, Gmail iOS, Gmail Android, Outlook iOS, Outlook Android, and Yahoo. ![MailSlurp device preview setup with green callouts around the selected client matrix and generated render address](/assets/guides/kit-device-rendering/01-mailslurp-device-address.webp) Copy the complete address from the active run. The address encodes the selected targets, so do not shorten it or reuse an address shown in a tutorial screenshot. ## Step 2: Prepare the final Kit message Open the Broadcast you intend to send. Confirm the visible From identity, reply handling, subject, preview text, images, links, personalization, footer, physical address, and unsubscribe content. Kit Broadcasts can be previewed as a subscriber or sent as a test email. Use the final subject, preview text, template, and sending address before starting the MailSlurp run. ## Step 3: Send the Kit test email In Kit, open the Broadcast editor and choose the preview or test-email action. Then enter the render address and send the test email. Use only the active MailSlurp render address for this device-preview run. ![Kit test-send screen with green callouts around the MailSlurp render recipient and send action](/assets/guides/kit-device-rendering/02-kit-test-send.webp) Wait for Kit to confirm that the test was accepted. Do not close the campaign until the saved content and recipient are correct. ## Step 4: Wait for every client to finish Return to MailSlurp. Receiving the Kit message starts the render automatically. Open the result and wait until every required target displays **Ready**. ![Completed MailSlurp Kit device preview with green callouts around the ready status and multi-client screenshots](/assets/guides/kit-device-rendering/03-mailslurp-device-results.webp) If a target reports a temporary capture failure, use its retry action and keep the completed captures. Approve the run only when the required target set is clean. ## Step 5: Inspect the delivered renders Open the highest-risk screenshots at full size and compare clients when needed. Check: - headline wrapping, body width, and reading order - mobile stacking and horizontal overflow - hosted image loading, cropping, dimensions, and alternative text - button contrast, width, spacing, and tap area - font fallbacks and line-height changes - Outlook Classic spacing and table alignment - light- and dark-mode contrast - footer, physical address, unsubscribe, and preference links If one client breaks, correct the Kit campaign and send the revised message to a new MailSlurp render run so the approval evidence clearly belongs to the latest version. ## Kit email preview checklist - The latest saved Kit revision was sent. - The final sender, subject, and preview text were used. - Representative personalization data was applied. - Every priority web, desktop, mobile, and dark-mode target is **Ready**. - Images load and scale without clipping. - Buttons remain readable and easy to tap. - Outlook Classic preserves the intended hierarchy. - Footer and unsubscribe content are visible. - The run was repeated after the last material edit. ## Troubleshooting ### MailSlurp does not detect the email Copy the active render address again, confirm Kit accepted the send, and make sure the address was not shortened or changed. ### Personalization is blank Update the test profile or contact values in Kit, preview the assembled content again, and send a fresh test. ### An image is missing in one client Use absolute public HTTPS image URLs, set useful dimensions and alt text, compare the failing client with another completed render, and retest the corrected campaign. ### Outlook spacing differs from Gmail Outlook Classic uses a different rendering engine from many web and mobile clients. Use email-safe table structure where needed, set explicit image dimensions, and rerun each correction. ## FAQ ### How do I preview a Kit email in Gmail and Outlook? Create a MailSlurp device preview, copy its render address, and send the final Kit test email to that address. MailSlurp captures the delivered message in the selected Gmail and Outlook targets. ### Can I preview Kit emails on iPhone and Android? Yes. Include iOS Mail, Gmail iOS, Outlook iOS, Gmail Android, and Outlook Android in the MailSlurp target set. ### Does the Kit editor preview replace email client testing? The editor is useful while composing. MailSlurp adds client-specific screenshots of the delivered message so reviewers can see rendering differences outside the editor canvas. ### When should I rerun the preview? Rerun after changing copy, contact data, images, links, layout, sender details, footer content, or campaign settings. Approve only the latest delivered version. After visual approval, continue with the [Kit inbox placement and spam score guide](/guides/kit-inbox-placement-testing/) to measure where the campaign lands.