Email Deliverability
The Ultimate Cold Email Delivery Checklist (2025 Edition)
Jun 6, 2025
Cold emails not getting opened? Landing in spam? Here’s how to fix every step that affects delivery and performance—without guessing.
Quick Summary
Before we go deep, here's the big picture of what this checklist will help you solve:

1. Define Your Target Audience (Before You Write)
Why it matters:
If your list isn’t relevant, even the best-written email won’t convert—and engagement (replies especially) is key to keeping your deliverability high.
Common Issue:
Scraped lists from tools like Apollo or ZoomInfo with no qualification. High bounce rates and “Who is this?” reactions.
How to Fix:
Segment lists by role, industry, and intent signal (e.g. hiring SDRs = good signal)
Run list cleaning through NeverBounce or Dropcontact
Use tools like Clay, PhantomBuster + LinkedIn filters to enrich context
2. Authenticate Your Sending Domain (SPF, DKIM, DMARC)
Why it matters:
You’re unverified without this—and inboxes assume you're spam or spoofing.
Common Issue:
You bought a domain and started sending without SPF or DKIM, or used a shared IP from your CRM.
How to Fix:
SPF (Sender Policy Framework) – Add a TXT record like:
DKIM – Enable in your email platform, copy the generated key to DNS.
DMARC – Start with this minimum policy:
p=none is a monitoring-only setting and won't protect your domain. Use p=quarantine at a minimum to begin improving your domain’s trust signals. Read more here →
Use MxToolbox to test your setup.
3. Warm Up Your Inbox (Don’t Skip This)
Why it matters:
Mailbox providers track how your domain behaves. Abrupt activity = red flag.
Warm-up Plan:
Week 1: 5–10 emails/day (with high reply simulation — 80%)
Week 2: 15–25/day
Week 3: 30/day
Use Mission Inbox, Mailreach, or Instantly
Advanced Tip: Warm replies should include real content (not gibberish) to boost “authenticity” signals.
4. Craft Compelling Subject Lines
Best Practices:
Use natural curiosity:
Avoid spam words:
Keep it short: 3–6 words is ideal
A/B test with small batches before full send.
5. Personalize the First Line
Why it matters:
Your first sentence appears in the inbox preview and determines open + reply rate.
Great first-line formulas:
“Saw your post about [TOPIC], curious what changed since then?”
“Congrats on [recent company news], how’s that going so far?”
Avoid fake personalization (“Loved your work at [company]”)—it backfires.
6. Avoid Spam Triggers (Words + Formatting)
🔥 Red flags include:
Excessive CAPS or punctuation (“BUY NOW!!!”)
Hyperlinks
Tracking links from public services like Bit.ly
Large images or attachments
Use Mailmeteor Spam Checker
Tip: Avoid HTML-heavy designs. Cold emails should look plain and personal.
7. Track Your Email Performance (But Don't Overdo It)
What to monitor:
Click rate → CTA clarity + trust
Reply rate → personalization + relevance
Bounce rate → list quality
Use tools with lightweight tracking (preferably via custom domains).
8. Limit Daily Volume + Randomize Timing
Why it matters:
Sending 200 cold emails in 3 minutes = bot behavior = block.
Best Practice:
Max 30 cold emails per inbox/day
Random delays between sends
Mix days and times (avoid rigid schedules)
9. Use a Plain-Text Unsubscribe Line (Even if Not Legally Required)
Why it matters:
It’s a spam complaint reducer—and inboxes use it as a positive signal.
Avoid unsubscribe links. These are a red flag in cold email and often lead to getting filtered or blocked, especially early in your domain’s sending life.
Instead, use a soft, plain-text opt-out, like:
“If this isn’t relevant, just let me know—I won’t follow up.”
10. Monitor Reputation + Placement (Not Just Delivery)
Tools to use:
GlockApps
Google Postmaster Tools
Mission Inbox inbox placement test (credit-based)
“Delivered” ≠ “Inboxed.”
Want to deepen your understanding of “delivered” vs. “deliverability”?
Click here for a clear breakdown of the difference—and why it matters.