How Email Content Affects Your Deliverability Score
The words you write, the links you include, and the way you format your email all influence whether it reaches the inbox. Here is how email content affects deliverability in 2026.
The words you write, the links you include, and the way you format your email all influence whether it reaches the inbox. Here is how email content affects deliverability in 2026.
Content analysis by email providers
Gmail, Microsoft, and other providers run content analysis on every incoming email. Their machine learning models are trained on billions of spam and legitimate emails, so they can identify patterns that humans might not notice. These models evaluate word choice, sentence structure, formatting, link density, and overall similarity to known spam.
Words and phrases that hurt
While there is no single "spam word" that automatically sends your email to spam, certain patterns increase your spam score. Using multiple promotional phrases (free, guaranteed, limited time, act now, exclusive offer) in the same email is a strong negative signal. Using language that does not match the conversational tone of a personal email (synergize, leverage, revolutionize, game-changing) can also raise flags. Write like you would write to a colleague. If your email sounds like ad copy, it will be treated like ad copy.
Link impact
Every link in your cold email is a potential liability. Email providers check links against known spam databases, evaluate the reputation of linked domains, and track link density. More than one link in a cold email is risky. Many deliverability experts recommend zero links in the first email of a sequence. If you must include a link, use your own domain or a well-known domain. Never use URL shorteners (bit.ly, tinyurl) — these are heavily associated with spam and phishing.
Image and attachment impact
Images add HTML complexity and increase the chance of promotion or spam placement. Attachments are even worse — they are a phishing vector and many corporate email filters block or quarantine emails with attachments from unknown senders. Never include images or attachments in cold emails.
HTML vs plain text
Plain text emails consistently outperform HTML emails for cold email deliverability. HTML adds code that spam filters analyze and that can trigger filtering. Plain text looks personal. In 2026, the highest-performing cold emails are plain text with minimal formatting.
The content checklist
Write in plain text. Keep the body under 80 words. Use conversational, natural language. Include zero or one link maximum. No images. No attachments. No HTML templates. No colored text, bold, or complex formatting. This is the content profile that passes spam filters most reliably.
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