Plain Text vs HTML Email: Which One Ecommerce Brands Should Send, and When

Ecommerce brands shouldn't choose plain text or HTML email for the whole program. Hayes Media, an agency that builds email, SMS, loyalty programs and subscribe-and-save for DTC brands, makes the choice per message: designed HTML for product-led campaigns, plain-looking notes for winback, review requests and post-purchase check-ins.

The reason is simple. A product launch has to show the product. A note asking how an order went has to read like a person wrote it. Below, you'll get the four formats people mix up, what each one does to images and tracking, how to write your preview text, and how to test the choice on your own list.

What's the difference between plain text and HTML email?

Plain text email has no images and no layout, and HTML email can have both. The confusion comes from two other formats that sit between them, so it's worth naming all four.

True plain text. Words only. GetResponse describes plain-text messages as having an "intentionally simplistic format (no images)". There's no logo, no button and no hidden image.

Plain-looking HTML. A message styled to look like a personal email. Klaviyo's text-only emails sit closest to this. Klaviyo says they "can look similar to a message you send from your personal inbox", but they can also "include images, change font styles and colors". So a Klaviyo text-only email isn't the same thing as true plain text.

Designed HTML. The branded template, with images, buttons and columns. In Klaviyo, that's usually the drag-and-drop editor.

The plain-text version of an HTML email. This is a second copy that travels with your designed email. Klaviyo says "When you send an HTML email, Klaviyo automatically includes a plain-text version", and that as a sender you can't tell which version your recipient views. Klaviyo also says its text only editor "is separate from the editor for an email's plain-text version", so these are two different settings.

Does plain text or HTML email convert better?

We haven't found a test that settles this for ecommerce revenue, so we won't tell you either one wins. The published claims come from email software vendors, and they measure clicks and opens rather than orders.

HubSpot published one such test. It says "In every single A/B test, the simpler-designed email won". Three details matter when you read that. HubSpot's plain versions weren't true plain text, because it says they had "hyperlinks, tracking pixels, etc." The survey in that article is dated 2014, and the article doesn't date its A/B tests. And it warns you directly: "ecommerce companies may have completely different results".

Klaviyo makes a softer version of the same claim: "While they aren't right for every use case, text-only emails often see higher click rates than fully designed HTML emails." Klaviyo doesn't publish the data behind that line on the page we read.

So treat a higher click rate as a reason to test plain-looking emails. It doesn't prove they'll bring in more money for your store.

Which ecommerce emails should be designed, and which should look plain?

Ask what the email has to do. If it has to show something, design it. If it has to feel like one person writing to another, keep it plain-looking. Hayes Media uses this split as a starting point on each message.

Product launches and sale campaigns: designed. The picture is doing the selling. You can see how we design them in these ecommerce email design examples.

Abandoned cart: usually designed. Your customer needs to see the item they left behind. These abandoned cart email examples show how that works in practice.

Welcome series: a mix. Klaviyo suggests a text-only email in your welcome flow "with a personal note about how your company got started". Your other welcome series emails can stay designed.

Winback: plain-looking is a good first test. A short note from your founder reads differently from another sale banner. Our winback email flow guide covers the timing and offers.

Review requests: plain-looking. You're asking a favor, and one clear link is all your customer needs. See our guide to the review request email.

Post-purchase check-ins: plain-looking. A question about how the order went should look like it came from a person. It fits alongside the rest of your post-purchase email flow.

Apologies and long emails: plain-looking. Klaviyo suggests text-only "When your company has made a mistake", and for long messages that are mostly text.

What changes when you take the design away?

You give up visual control, and you lose some tracking. You also shrink a few risks that come with heavy templates.

Images. A designed email depends on them, and they won't always show. Google says "By default, when you get an email with an image, you'll see the image automatically", but a reader can choose to "Ask before displaying external images". It also says that if Gmail thinks a sender or message is suspicious, "you won't see images automatically". If your offer only exists inside an image, a reader without images doesn't see your offer. Put it in live text as well.

Links. A true plain text email has no buttons, so the link has to make sense by itself. Google's sender guidelines say "Web links in the message body should be visible and easy to understand".

Open tracking. Klaviyo says it "tracks when a customer opens an email using a clear pixel". True plain text has no image to carry one. GetResponse says "any message you send as plain-text will always show an open rate of zero, no matter how many subscribers open the message". That's GetResponse's own platform, and the Klaviyo text-only page we read doesn't say how opens behave there, so check a test send in your account before you compare numbers. Our email open rate benchmarks piece covers how to read opens in general.

Clipping. Heavy code can get your email cut off in Gmail. Klaviyo says "On desktop devices, the email size limit is generally 102 KB", and that this limit "does not include image file sizes". It adds that if the tracking pixel is in the clipped portion, "opens may not be recorded". The more template code you send, the closer you get to that limit.

Accessibility. Klaviyo says a long, mostly text email "will be easier for screen readers, smart watches, and other assistive technology to read". If you send designed emails, the W3C's guidance helps: "If the image is not a logo, avoid text in images". When you do use one, "the text alternative should contain the same words as in the image".

Deliverability. Google's guidelines don't favor a format on the page we read. They say "If your messages are in HTML, format them according to HTML standards". HubSpot's view is that "your HTML and plain-text should have the same deliverability metrics" if your code is clean and you include a plain-text version. We wouldn't switch format to fix a deliverability problem until you've checked your authentication and your list.

What's email preview text, and how should you write it?

Preview text is the line that sits beside your subject line in the inbox, and you should always set it yourself. Klaviyo says it's "displayed in the inbox after the subject line of an email".

If you skip it, the inbox fills the gap. Klaviyo says "inboxes automatically pull it from the beginning of your email" and "This can include alt text or your navigation bar". That's how a designed email ends up previewing its own menu.

A plain-looking email has a different problem. The start of your email becomes the preview, so a first line like "Hi Sam" uses up that space. Either way, write it on purpose:

Add to the subject line. Don't repeat it. Use the preview to say what's inside.

Keep it short. Klaviyo says "Keep preview text concise" and that "smaller screens" display fewer characters. It treats character counts as examples, so test in the inboxes your customers use.

Use the right field. Klaviyo says its upgraded text only editor "has a dedicated Preview text field". Earlier, you "had to add preview text manually as HTML".

Be careful with hidden text. Google says "Don't use HTML and CSS to hide content in your messages", because it "might cause messages to be marked as spam". Keep your preview honest about what's in the email, and don't load hidden copy into the top of your template.

How do you test plain text against HTML on your own list?

Send both versions to a random split of one segment, change only the format, and judge on revenue per recipient. Don't judge on opens. SendGrid says Apple's Mail Privacy Protection means senders can't tell a real open from a pre-fetch, "which makes open statistics unreliable", and a true plain text version may not report opens at all.

Here's a worked example, and these are made-up numbers. You split 20,000 lapsed customers into two groups of 10,000 for a winback email. The designed version gets 180 clicks, 12 orders and $840 in revenue. The plain-looking version gets 240 clicks, 11 orders and $770 in revenue.

Clicks favor the plain version. Revenue per recipient favors the designed version, at $0.084 against $0.077. One order separates them, so this test hasn't told you much. Run it again on the next send before you change the flow. For a longer view, compare gross profit per customer, because lifetime gross profit to CAC is the scoreboard that decides what you can afford to spend on acquisition.

When this does not apply

Your product needs to be seen. If the picture makes the sale, a plain note can start the conversation but it won't replace the image. Use a designed email, or link to a page that does the showing.

Your list is small. A test with a handful of orders can't tell you much. Choose by what the message has to do, and put your effort into the offer.

You'd have to fake the personal touch. A founder note only works if a person stands behind it and replies are read. Don't dress a promotion up as a reply either. Google says not to use subject lines starting with Re: or Fwd: "unless the messages are actual replies or forwards".

Your own results disagree. If your data says your customers buy more from designed winback emails, keep sending those. Your numbers beat our starting point.

How does Hayes Media handle this for clients?

Hayes Media makes the format choice message by message inside your email and SMS program, which also covers loyalty programs and subscribe-and-save. We work in Klaviyo for most accounts and have experience in most other email and SMS platforms.

We work with brands doing at least $100K per month in revenue. That's a guideline, and a smaller brand with a clear budget set aside to scale and real order volume can still be a fit.

On proof, our retention practice lists "$500M+" in client revenue driven, and one account went from "0% to 59% of Revenue from Retention". Those figures are published by Hayes on its own site. Hayes has no third-party review profile and no Klaviyo partner listing, and neither figure is a result of email format alone.

One-time email projects start from $2,000 USD, and retainers for ongoing full management start from $4,000 USD per month, scoped on the discovery call.

Book a discovery call if you'd like an audit of your email program, including which of your flows and campaigns should be designed and which should look plain. No onboarding fees. No lock-in contracts. No junior marketers.

Sources

Google: Email sender guidelines. Message formatting, links, hidden content and subject lines.

Google: Turn images on or off in Gmail. Default image behavior and the ask-first setting.

Klaviyo: How to create a text-only email. What text-only emails can include, suggested uses, the click rate claim and screen readers.

Klaviyo: How to edit the plain text version of an HTML email. The automatic plain-text version.

Klaviyo: How to insert preview text into an email. Placement, blank fields and character counts.

Klaviyo: About the upgrade to Klaviyo's text only editor. The preview text field and the separate plain-text editor.

Klaviyo: Why is my email being clipped?. The size limit and tracking pixel risk.

Klaviyo: How to edit the location of your tracking pixel. How opens are tracked.

GetResponse: My open rate statistics are not available. Plain-text messages and open rates.

HubSpot: Plain Text vs. HTML Emails. Vendor A/B tests and the ecommerce caveat.

SendGrid: Understanding Apple Mail Privacy Protection and Open Events. Pre-fetching and open statistics.

W3C: Images Tutorial. Text alternatives and text in images.

Hayes Media retention practice. Source of the retention figures.