Good question. A few people have asked this.

I think there's a time and place to use rich HTML emails (and a time and place not to).

For me the time to is newsletters, promotional emails, great-big new feature emails etc. The sort of time you want to showcase something great.

However system emails, like password resets and invitations are times when you need to be efficient. I don't think they should be rich HTML emails.

System emails are not for looking at and enjoying, they're there to make the system run as smoothly as possible. To get the user from A to B.

Mailrox is all about speeding up development. It was a really tricky decision to make the invite email non-fancy, but I think it's the right one. If you see what I mean.

I agree with your premise that password resets and system emails for a typical app shouldn't be HTML, but for you I really think they should be. It's your whole product and a perfect opportunity. If I get a really sharp clean welcome email or password reset, etc... I'm much more likely subconsciously associate your app with beautiful emails.

I completely agree. These days there's very little wrong with sending HTML-based transactional email provided you've covered your bases on all other potential flags and send as multipart with a plaintext component. At PostageApp many clients have amazing inbox delivery with HTML transactional, and the benefits - improved tracking, better funnel direction etc. - outweigh the minor delivery drawbacks in many cases.

Frankly, many who send 'plaintext' transactional in fact end up sending as HTML these days in order to facilitate open tracking from embedded images, so aren't gaining much beyond avoiding the minor issues like 'HTML_IMAGE_RATIO' etc.

edit Apparently the MailRox invite email _is_ an HTML email for the exact reasons outlined above. I can see no reason why you wouldn't want to add some visual sparkle to this based on that fact. Incidentally, you're sending without a plaintext component which can cause delivery problems at some ISPs.

You're right, I'm really on the fence with this, it's a hard one. I'm going to look into getting a light-weight HTML email for the system notifications. If the right balance can be struck I'll go for HTML.

Edit: When I say HTML I mean well designed (boxes, colors and logos). At the moment, like tomwalsham said, its just some <p> tags.

Just to add my voice to the thread above—I also thought it was odd to get a plain-jane invite email. The overall idea of the app is really enticing to me though because I really hate coding up emails using the old-school tables, font-face, etc.

You can use mime types to send both HTML and plain text so that the receiver can choose which to view based on the mail client preference. Some of us still like to use mutt or (al)pine for mail and either have to render html in w3m or something if text is not also included.

As it will be the first time people see your product's output, the welcome email (and every other email you send) is a promotional email where you want to showcase something great.