Testing email campaigns on multiple devices

If you need to test emails and how they look on multiple devices, I recommend using Litmus. 

You should test how emails look on different devices because email html still uses tables, and webmail services strip out doctype, body, and head tags including inline css, meaning your fancy emails may look awful on some devices. Yes,you can resort to sending plain text emails,  but it'll definitely lack the panache you were seeking.