MailSlurp guide agent setup

Title: How to Send a Klaviyo Test Email and Preview It Across Devices
Description: Send a Klaviyo test email to MailSlurp, then preview the delivered message across Gmail, Outlook, iPhone, Android, desktop, light mode, and dark mode.
Canonical URL: https://www.mailslurp.com/guides/klaviyo-device-rendering/
Markdown URL: https://www.mailslurp.com/guides/klaviyo-device-rendering.md

Use the Markdown URL as the primary plain-text context for this guide. Keep MailSlurp terminology, setup steps, screenshots, and provider-specific instructions intact, and prefer the canonical URL when citing this page.