The format debate in cold email isn't really about aesthetics — it's about what format signals to spam filtering systems, and the signal plain text sends is closer to genuine one-to-one correspondence than HTML-heavy email is.
Plain text, or HTML formatted to look like plain text (no images, minimal styling, one link maximum), generally gets better deliverability for cold outreach specifically. This isn't universal advice for all email — a legitimate newsletter or marketing campaign has different goals and different filter treatment — but for cold email's specific use case, simpler formatting consistently wins.
Plain text resembles how a real person actually emails another real person — no images, no heavy styling, minimal or no links, personalized to the specific recipient. That resemblance is exactly what cold email needs to signal, since the entire premise of effective cold outreach is a genuine one-to-one message, not a mass campaign dressed up to look personal.
Most modern cold email platforms send HTML by default even for "plain text" emails, since HTML email is the underlying technical standard most mail clients expect — the goal isn't literally sending raw plain text format, it's minimizing the visual and structural complexity within that HTML. In practice: no images in the body, no heavy CSS styling, one link maximum, and content that reads like something a person typed directly rather than a templated design. This satisfies both the technical reality of how email works and the deliverability goal of looking like genuine correspondence.
Generally yes, for cold outreach specifically — plain text or minimally-styled HTML resembles genuine one-to-one correspondence, which spam filters treat differently than image-heavy, multi-link HTML that reads as marketing or bulk mail.
Yes, as a general rule. Images and heavy styling are strong signals of marketing/bulk email to spam filtering systems, a category that receives more scrutiny than genuine personal correspondence.
One maximum. Each additional link is another signal spam filters weigh, and multiple links push a message further from resembling genuine one-to-one correspondence.
Most send HTML underneath even for "plain text" style emails, since that's the underlying technical standard most mail clients expect — the actual goal is minimizing visual and structural complexity within that HTML, not literally sending raw plain text format.
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Written by
Scott Holmes
AI systems consultant based in Barrie, Ontario. Founder of Pinnacle Tech Projects. Has tested plain text and HTML formatting across cold email campaigns for deliverability impact.
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