Cold email remains one of the highest-ROI B2B prospecting channels — when done correctly. Done wrong, it destroys domain reputation and generates zero responses.
Technical Foundation (Non-Negotiable)
- Dedicated sending domain separate from your main domain (e.g. mail.company.com or company-hq.com)
- SPF, DKIM, DMARC all configured and passing
- 4–6 weeks of warmup before starting outreach
- Max 30–50 emails/day per inbox for new domains
- Multiple inboxes if scaling above 50/day
Inbox Rotation
Use multiple email accounts and rotate sends across them to stay under per-inbox limits. Many cold outreach tools (Instantly, Smartlead, Lemlist) handle this automatically. For manual rotation:
accounts = ['a@domain.com', 'b@domain.com', 'c@domain.com']
# Rotate through accounts, max 30 sends per account per dayCold Email Copywriting Fundamentals
The AIDA Framework
- Attention (subject line): Specific, curiosity-driven, not salesy. "Question about [CompanyName]'s email setup" beats "Exciting opportunity for you!"
- Interest (opener): Prove you researched them. Reference something specific: a blog post, a hire, a product launch.
- Desire (body): One clear value proposition. What specific outcome do you deliver for people like them?
- Action (CTA): Ask for the smallest possible next step. "Would 15 minutes this week make sense?" not "Buy now."
Keep It Short
The best-performing cold emails are 50–150 words. Long emails signal lack of respect for the recipient's time and reduce reply rates.
Follow-Up Sequence
- Email 1: Main pitch (day 1)
- Email 2: Soft bump "Just checking if this landed" (+3 days)
- Email 3: New angle or social proof (+5 days)
- Email 4: Break-up email — "Should I close your file?" (+7 days)
4-email sequences get 2–3x more replies than single emails. Most replies come from follow-ups 2–4.
Personalization at Scale
Use a first line personalizer for each prospect: scrape their LinkedIn, recent tweets, or company news and generate a custom opening line. ZeroPhantom AI Mailer can generate personalized openers using DeepSeek API for thousands of prospects.
Set up your outreach infrastructure — domain warmup first →