What is plain-text copywriting vs HTML design copywriting?

Open a transactional email from your bank and you'll typically see a logo, formatted text, and a styled button. Now look at an email from a founder you follow or a personal newsletter, and you might see nothing but text, like a message typed in a mail app. That second kind is a plain-text email, and writing copy for it requires a different approach than writing for a designed HTML template.

HTML email copywriting works within a layout. Your headline already has visual hierarchy, your CTA is a styled button, and images carry some of the message. The copy's job is to support the design without fighting it: shorter blocks, punchier lines, calls-to-action that complement the visual elements around them. Plain-text copywriting has none of that scaffolding. Every link needs to be labeled clearly, emphasis comes from word choice rather than bold or color, and the entire subscriber experience is your writing. It's more demanding to do well because there's nowhere for weak sentences to hide.

Some email types default to one format. Transactional emails (receipts, password resets, shipping confirmations) are often plain-text or near-plain-text by convention because they feel more official and render consistently everywhere. Promotional emails usually use HTML templates. But the divide isn't rigid: many high-performing newsletters and sales emails use plain text or minimal HTML specifically because it feels personal and signals that a human wrote it, not a drag-and-drop builder.

There's also a practical infrastructure reason to care about plain-text copy: every HTML email should include a plain-text alternative (the multipart/alternative MIME type). Some corporate mail gateways and older clients prefer or require it. If your HTML images are blocked, the plain-text part is what subscribers see. Use strong alt text on all images in your HTML version, and make sure your plain-text copy doesn't just strip HTML tags from your designed email but reads naturally on its own. Review My Emails lets you preview both the HTML and plain-text renders before sending, so you can confirm neither version is broken. For a deeper look at when each format wins, see HTML vs plain text emails.