MailSlurp guide agent setup

Title: How to Preview Omnisend Emails in Gmail, Outlook, iPhone, and Android
Description: Send an Omnisend test email to MailSlurp and preview the delivered campaign across Gmail, Outlook, Apple Mail, iPhone, iPad, Android, desktop, light mode, and dark mode.
Canonical URL: https://www.mailslurp.com/guides/omnisend-device-rendering/
Markdown URL: https://www.mailslurp.com/guides/omnisend-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.