Send email marketing messages as multipart/alternative

Should you send your newsletter in plain text and abandon the advantage of rich HTML formatting? Or should you risk annoying some who detest HTML more than anything else?
Fortunately, email has an elegant and almost universal solution to this dilemma: multipart/alternative messages.

Multipart/alternative emails contain both a plain text and a HTML part. Which part is shown to the user is determined by their email client, and (in some cases) by their choice.

If an email client cannot render HTML messages, it will display the plain text version. HTML-enabled email programs will usually show the rich HTML version, but some let the user decide which they prefer.

With multipart/alternative messages just about everybody gets the best of both worlds, and you don't have to ask users for their preference and maintain two separate subscriber lists. The only disadvantage of multipart/alternative messages is their (slightly) larger size, but as network capacities grow, this is almost negligible.

To send your email marketing messages as multipart/alternative: Make sure your email marketing software or service provider supports multipart/alternative messages. Compose both a rich HTML version of your message and a plain text equivalent. Send them both together as one multipart/alternative message.