Email Deliverability for Cold Outreach: How to Stay Out of Spam
# Email Deliverability for Cold Outreach: How to Stay Out of Spam
You can write the best cold email in the world. If it lands in spam, nobody sees it. Deliverability is the foundation everything else sits on.
Domain Setup (Do This First)
Before sending a single email, set up these three DNS records. Without them, inbox providers will flag your emails immediately.
SPF (Sender Policy Framework): Tells receiving servers which IP addresses are allowed to send email from your domain. Without it, anyone could send email pretending to be you.
DKIM (DomainKeys Identified Mail): Adds a digital signature to your emails proving they haven't been tampered with in transit.
DMARC (Domain-based Message Authentication): Tells receiving servers what to do with emails that fail SPF or DKIM checks. Start with a monitoring policy, then move to reject.
Your email provider (Resend, SendGrid, Mailgun, etc.) will give you the exact records to add. It takes 10 minutes.
Warm Up Your Domain
A brand new domain sending 500 emails on day one will get flagged. Inbox providers track sending volume over time. A sudden spike from a new domain looks like spam.
Week 1-2: Send 10-20 emails per day to real recipients (not yourself). These should be genuine emails that get replies.
Week 3-4: Scale to 50-100 per day.
Month 2+: Scale to your target volume (200-500 per day).
If you need to send high volume immediately, consider using a secondary domain for cold outreach to protect your primary domain's reputation.
Volume and Pacing
Never send 500 emails at 9:00 AM on the dot. That's what spam bots do.
Space your emails throughout the business day with random gaps between each send. 30-60 seconds between emails, spread across 9 AM to 4 PM. This mimics how a real person would send emails.
Content That Avoids Spam Filters
Avoid spam trigger words: "Free," "guaranteed," "act now," "limited time," "buy now," "congratulations." These are heavily flagged.
Keep it short: Long emails with lots of links trigger spam filters. One link maximum. Three to five sentences.
No images in cold emails: Plain text or minimal HTML. Images, especially with tracking pixels, can trigger spam filters.
Include your real business address: It's a legal requirement in many countries and inbox providers check for it.
Bounce Rate
Keep your bounce rate below 3%. Hard bounces (invalid email addresses) damage your sender reputation quickly. If you're scraping leads, make sure the emails you're sending to are real and active.
Monitor Your Reputation
Check your domain's sender reputation regularly using tools like Google Postmaster Tools (free), MXToolBox, or SenderScore. If your reputation drops, reduce volume immediately and focus on sending to engaged recipients only.