Why plain-text emails still beat fancy HTML ones in cold outreach
A branded template signals 'campaign' to filters and humans alike. In cold outreach, the plainest-looking email is usually the one doing the least damage.
By Norbelys Chirinos, Co-founder
Founder-reviewed ·How we research and correct articles
Open your own inbox and look at the emails you actually replied to this month. Chances are good most of them didn’t have a logo, a colored button, or a footer with five social icons. They looked like something a person typed to you directly — because that’s usually exactly what they were.
That’s not nostalgia for the plain-text era. It’s the reason plain text still quietly outperforms designed HTML in cold outreach specifically, even in 2026, even though HTML templates dominate almost every other kind of email a business sends.
Reason one: HTML is gambling that your design will actually render
A plain-text email has almost nothing that can break. An HTML email is a small web page, rendered by whatever engine the recipient’s client happens to use — and those engines don’t agree with each other. Outlook’s desktop apps have historically rendered HTML email through Microsoft Word’s layout engine rather than a real browser engine, which is exactly as unpredictable as it sounds for anything beyond simple text and a link.
Images make this worse, and the gap here is measurable, not anecdotal. Litmus’s analysis of image-loading behavior in Gmail found that images are blocked by default in roughly 43% of the emails it tracked. That means close to half the time, a carefully designed template with a logo and a styled call-to-action button renders as a wall of broken image boxes on first open — the exact opposite of the polished impression it was built to create. A plain-text email has no image to fail to load in the first place.
Image blocking isn’t even the only rendering hazard. Roughly a third of email opens now happen with the client’s dark mode turned on, and dark mode doesn’t just invert a background color — it can invert your carefully chosen brand palette into something illegible, turn a white logo on a transparent background invisible, or leave a colored button looking washed out against a background it was never designed for. On mobile, a template built for a wide desktop layout regularly gets clipped mid-message by the provider’s size limit, hiding the footer, the unsubscribe link, and whatever came after the cutoff. Plain text sidesteps essentially all of this: there’s no color scheme to invert, no fixed-width layout to clip, and no logo image to disappear.
Reason two: heavy HTML reads as “campaign” to both machines and humans
[Spam filters increasingly score mail using a content model trained to recognize what marketing mail generally looks like] (/blog/whats-actually-happening-inside-a-spam-filter/) — and a heavily templated email, full of nested tables, tracking pixels and styled buttons, is a strong structural signal of exactly that category, independent of what the words actually say. Gmail’s Promotions tab classifier works on a related principle: mail that’s structurally built like a marketing send gets treated like one, landing in a tab most people check far less often than their primary inbox, even when the sender authenticated everything correctly.
Humans run roughly the same pattern-match, just consciously. A heavily designed template reads, instantly, as “someone sent this to a list.” A plain block of text with your name in the greeting reads as “someone wrote this to me.” One of those gets ignored the way marketing gets ignored. The other gets read the way a message from a colleague gets read — and cold outreach is trying to earn the second reaction, not the first.
Reason three: plain text can still be fully compliant
The one objection worth taking seriously: doesn’t dropping the HTML template mean losing the unsubscribe link and the tracking you need to run the program responsibly? No — and this is where the mechanics actually help you. One-click unsubscribe under RFC 8058 works through message headers, not a styled button in the body, so a plain-text email can be just as compliant as a fully designed one. Open and click tracking can still work through a plain link and a lightweight pixel; you just don’t need five hundred lines of nested table markup to get there.
A cold email that reads as plain text without losing function
Write it as if you're the only recipient
One paragraph greeting, a specific reason you're reaching out, one clear ask. No hero image, no logo block.
Keep formatting to line breaks and, at most, one link
Bold and colored buttons are the first thing a busy reader's eye flags as 'not personal.' A plain hyperlink does the job.
Add compliance in the headers, not the body
List-Unsubscribe and List-Unsubscribe-Post headers satisfy the one-click requirement without a visible unsubscribe button breaking the plain-text feel.
Track what actually matters
A single tracked link and a lightweight open pixel are enough signal for reply-focused outreach — you don't need click heatmaps on an email that has one link in it.
This is also worth separating from a related but distinct question: whether to send from a plain personal-style address or a branded one, and whether to include a company footer at all. Compliance rules like CAN-SPAM still require a physical address and clear sender identification regardless of format — going plain text isn’t a way to skip those requirements, just a way to satisfy them without the visual weight of a full template. A one-line footer with your name, company and address reads as plain text just fine; it’s the banner, the button and the multi-column layout above it that create the risk this post is actually about.
What the data actually supports, and what it doesn’t
It’s worth being precise here instead of overselling the case: rigorous, independently verified reply-rate comparisons of plain text versus HTML specifically for cold outreach are hard to find — most of the numbers floating around the industry come from individual vendors’ own platform data, without published methodology or controls for list quality, audience, or offer. What’s solidly documented is the rendering-risk piece above — the Litmus image-blocking figure is real, measured, and provider-specific. The categorization and personal-feel arguments are consistent with how spam filters and Gmail’s tab system are documented to work, even without a single definitive reply-rate study to point to. Treat the rendering and categorization arguments as the load-bearing ones; treat any specific reply-rate multiplier you see quoted elsewhere with appropriate skepticism.
Frequently asked questions
Should I strip all formatting, including bold text and paragraph breaks?
No — line breaks, occasional bold for emphasis, and a single plain hyperlink don't trigger any of the risks described here. The line to avoid crossing is structural HTML: multi-column layouts, background colors, embedded images, and styled buttons, since those are what break in rendering and read as templated to both filters and recipients.
What about a company logo in the signature — is that still safe?
A small, simple signature image is lower risk than a hero banner at the top of the email, but it's still an image that can fail to load by default in a meaningful share of opens. If you use one, keep the email fully readable and complete without it ever loading.
Does this apply to warm follow-ups with an existing customer too, not just cold outreach?
The rendering risks are universal, but the categorization and personal-feel argument is strongest for a first message to a stranger. Once someone has an existing relationship with your brand, a lightweight branded template carries less risk of reading as an unwanted campaign.
Where this leaves your next cold campaign
None of this means abandoning every visual element forever — it means being honest about what a first cold email to a stranger is actually for. It’s not a brand impression. It’s a message asking someone who’s never heard of you to spend thirty seconds reading it and consider replying. The plainer that message looks, the more it resembles the kind of email people already open and answer without thinking twice.
Norbelys’s program builder is built around that reality rather than against it: sequences are written as real messages with merge fields and conditional blocks, not dragged-and-dropped from a template library, and analytics count real human opens and clicks — not inflated by tracking-pixel noise — so you can judge a plain, personal sequence by the metric that actually matters for cold outreach: replies, not impressions. Start sending with Norbelys and build the kind of cold sequence that reads like it came from a person, because that’s still what gets answered.