How to Avoid Spam — Practical Rules

Landing in spam is the main problem with cold-email. After you have configured SPF/DKIM/DMARC and connected SMTP, it remains to work with content and behavioral factors.

Email Content

1. No CAPS — not even in one word. "FREE" or "URGENT" in the subject line is instant spam.
2. Trigger words: free, $$$, act now, limited time, discount, click here, guaranteed, money back. Each provider has a complete list of ~200 words. In Postigo, the editor underlines such phrases as you type.
3. Long paragraphs — a wall of text looks like marketing. Break it down into 2-3 sentences with a blank line.
4. Excessive HTML markup — tables, buttons, images. In the first email, all this is worse than simple text. Plain text is less likely to go to spam than complex HTML markup.
5. Links in the first email — there should be none. Postigo automatically adds one unsubscribe link, which is enough. Your own links are only in the follow-up.

Email Subject Line

• 4-7 words is optimal
• Personal appeal via {{name}}
• A question or intrigue works better than statements
• No [brackets], (parentheses), emojis in the first campaign
• Use spintax {Hi|Hello|Hey} {{name}}, {quick|tiny} question to make the subject different for each recipient

Technical Factors

1. Bounce rate < 2%. Run the database through an email validator. If the bounce rate increases, stop the campaign and clean the database.
2. Spam complaints < 0.1%. The fewer people who click "Spam," the better the reputation. Relevant databases and a clear sender reduce complaints.
3. Reply rate > 1% is a positive signal for providers. The more recipients respond, the better the reputation.
4. Regularity — better 100 letters a day every day than 700 times a week
5. Sending time — working hours of your target audience. Emails at night open worse and are often marked as "not on time" (which reduces engagement)

Recipient Lists

The most common cold-email mistake is a bad database. Signs of a bad database:

• Purchased without targeting
• Old (addresses without updates > 6 months)
• With a large % of role-based addresses (info@, sales@, support@) - they have bounce and spam complaints several times higher
• With a large % of free domains (gmail/yahoo/hotmail) for a B2B task

Clean the database through an email validator before sending. Remove role-based addresses. Segment by company/industry.

Testing Before Mass Mailing

Create a small test campaign (10-20 emails) to your own addresses in Gmail, Outlook, Yahoo, Mail.ru. Check where the letter goes — to the inbox, to Promotions, to Spam.

A useful service is mail-tester.com. Send a test email to their address, get a score of 0-10 and a list of comments on content, subject lines, authentication. 8/10+ — the campaign can be launched.

If You Already Landed in Spam

Don't panic. Constant spamming is a reversible process:

1. Stop all mailings on this SMTP for 3-7 days
2. Check SPF/DKIM/DMARC via mxtoolbox
3. Check blacklist via Blacklist Checker
4. Reduce the daily volume by 2-3 times
5. Resume with a very clean database and positive content (without trigger words)
6. After 2-3 weeks of stable operation, the reputation will be restored