Litmus is a quality email testing service.

I use Litmus to test how my emails look across different providers, so I can see if the different visual elements that I use look consistent across platforms. This allows me to make sure that all of our customers are receiving quality emails and that no one email provider is receiving lower quality. I recently have started using Litmus to use personalization tools in emails as well, such as countdown timers. Other users across my organization use Litmus for HTML testing.

This is not applicable to our organization as we do all of our engagement and performance metric tracking within our ESP, however the deeper visibility into email design and quality across different providers has allowed me to gain confidence in my email marketing strategy as I can know that all of our customers are receiving our emails in the way that I intended.

I have just started using the timers in the personalization tab, and I think they have been a great way to add some visual elements to emails. I had previously been making these on third party websites, however, with this new tool it's great to keep it all within one platform. One thing I would change about these timers is that they are automatically set to a 600 px background, and that can't be edited. Additionally, I think it would be interesting if these could be saved as gif images rather than HTML code so that I could place a link behind the timer.