Cold Email Deliverability Checklist (Download-Ready)
The 27-item checklist that covers every technical, content, and behavioral factor affecting whether your cold emails reach the inbox. Grouped by category with what to check, why it matters, and how to fix each item.
LeadHunt finds verified B2B contacts and runs 29-point website audits, then lets you outreach via email, WhatsApp, and SMS — with transparent flat pricing. This deliverability checklist ensures the emails you send through LeadHunt (or any cold email platform) actually reach the inbox. According to Validity's 2025 Email Deliverability Benchmark, senders who follow a structured deliverability checklist achieve 91% average inbox placement versus 67% for those who do not.
The checklist is organized by category in priority order. If you are short on time, complete the DNS Setup section first — it addresses the most common and most damaging deliverability issues. Each item includes what to check, why it matters, and how to fix it if it fails.
Last updated: April 2026
DNS Setup
SPF record exists and passes
Why it matters: SPF tells inbox providers which servers can send from your domain. Without it, any server can spoof your domain.
How to fix: Add TXT record: v=spf1 include:your-esp.com ~all. Verify with MXToolbox SPF Lookup.
DKIM signing enabled and valid
Why it matters: DKIM cryptographically proves each email was sent by you and was not tampered with in transit.
How to fix: Enable DKIM in your ESP settings. Add the public key TXT record. Verify with DKIM Validator.
DMARC policy published
Why it matters: DMARC tells providers what to do when SPF or DKIM fails. Without it, providers make their own (often aggressive) decisions.
How to fix: Add TXT record: v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com. Upgrade to p=quarantine after 30 days.
Custom tracking domain configured
Why it matters: Default tracking domains are shared with other senders. Their bad behavior affects your reputation.
How to fix: Set up a CNAME record for track.yourdomain.com pointing to your ESP tracking server.
MX records point to valid mail server
Why it matters: Domains without MX records cannot receive replies, which looks suspicious to spam filters.
How to fix: Ensure your domain has MX records pointing to your email hosting provider.
Reverse DNS (PTR) record matches
Why it matters: PTR records validate that your sending IP resolves back to your domain. Mismatches flag as spoofing.
How to fix: Contact your ESP or hosting provider to set up PTR records. Most cloud ESPs handle this automatically.
Content
Subject line free of spam triggers
Why it matters: Words like "free," "guaranteed," "act now" increase spam scoring, especially from new domains.
How to fix: Use conversational, specific subject lines. Test each subject in Mail-Tester before sending at scale.
Email body is plain text or minimal HTML
Why it matters: Heavy HTML templates with images and complex layouts score higher on spam filters than plain text.
How to fix: Send plain text or very light HTML. If using HTML, ensure text-to-code ratio exceeds 60%.
Maximum 1 link in body (excluding unsubscribe)
Why it matters: Multiple links is a strong spam signal for cold emails. Each additional link increases spam probability.
How to fix: Include only your primary CTA link. Remove social links, website links, and signature URLs.
No image attachments or embedded images
Why it matters: Images cannot be scanned by text-based content filters and increase overall spam scoring.
How to fix: Remove all images from cold email templates. Use text descriptions instead.
Personalization in first line and subject
Why it matters: Identical content sent to many recipients is the primary signal of bulk spam.
How to fix: Personalize at minimum: recipient name, company name, and one specific detail per email.
Unsubscribe mechanism present
Why it matters: Required by CAN-SPAM and Gmail sender requirements (June 2024). Missing unsubscribe triggers aggressive spam filtering.
How to fix: Add one-click unsubscribe link. Include List-Unsubscribe header for automated processing.
No URL shorteners (bit.ly, tinyurl)
Why it matters: URL shorteners are heavily abused by spammers and phishers. Major inbox providers flag them.
How to fix: Use full URLs on your own domain. If you need tracking, use your custom tracking domain.
Sender name is a real person, not a company
Why it matters: Emails from "John at Acme" get 15% higher open rates than "Acme Corp" (Woodpecker 2025 Cold Email Study).
How to fix: Set sender name to your real first name or "First Name at Company."
Sending Behavior
Domain warmed up for 14+ days
Why it matters: New domains with no sending history are treated as suspicious. Warmup builds the positive engagement signals providers need.
How to fix: Complete the 14-day warmup protocol before any cold campaign. See our warmup guide.
Daily volume within safe limits
Why it matters: Exceeding your established daily volume by more than 30% triggers automated throttling.
How to fix: Start at 50 emails/day post-warmup. Increase by 20-25% per week. Never exceed 200/day per mailbox.
Send times spread across business hours
Why it matters: Blasting all emails at once (e.g., 200 emails at 9:00 AM) looks automated and triggers rate limiting.
How to fix: Spread sends across 8 AM - 5 PM recipient local time with 30-90 second random delays.
Using multiple sending accounts for volume
Why it matters: Sending 500 emails from one mailbox is far riskier than 100 emails each from 5 mailboxes.
How to fix: Set up 3-5 mailboxes per domain. Rotate sending across accounts. Use inbox rotation tools.
Warmup running alongside campaigns
Why it matters: Ongoing warmup maintains a baseline of positive engagement that protects against occasional spam complaints.
How to fix: Keep warmup active indefinitely at 20-30% of total daily send volume.
Monitoring
Bounce rate tracked per campaign
Why it matters: Bounce rates above 3% damage sender reputation and can trigger blacklisting.
How to fix: Check bounce rates after every batch. Pause if any batch exceeds 3%. Clean list before resuming.
Spam complaint rate below 0.1%
Why it matters: Gmail and Microsoft flag senders with complaint rates above 0.1% as bulk spam.
How to fix: Monitor via Google Postmaster Tools. If complaints spike, audit your targeting and content.
Reply rate tracked as health metric
Why it matters: A sudden drop in reply rate (more than 50% week-over-week) often precedes spam placement by 3-5 days.
How to fix: Track reply rates weekly. Investigate immediately if rates drop significantly. See our reply rate guide.
Weekly inbox placement test
Why it matters: Open rates do not distinguish inbox from promotions tab. Only placement tests show true deliverability.
How to fix: Send test emails to seed accounts weekly via Mail-Tester or GlockApps.
Blacklist monitoring enabled
Why it matters: Being listed on a blacklist can drop inbox placement from 90% to under 20% overnight.
How to fix: Set up free alerts at MXToolbox or HetrixTools for your domain and sending IPs.
Tools & Infrastructure
Email verification before every send
Why it matters: Unverified lists contain 15-30% invalid addresses that generate hard bounces and damage reputation.
How to fix: Run every list through ZeroBounce, NeverBounce, or MillionVerifier before uploading to your sending tool.
Dedicated domain for cold outreach
Why it matters: Cold email carries inherent reputation risk. Using your primary domain exposes client communication to that risk.
How to fix: Register a secondary domain (e.g., getbrand.com, trybrand.io). Set up full DNS authentication.
Google Postmaster Tools connected
Why it matters: GPT provides Gmail-specific domain reputation, spam rate, and authentication data that no other tool surfaces.
How to fix: Verify your domain at postmaster.google.com. Check weekly for reputation changes.
How to use this checklist
Run through all 27 items before launching a new cold email campaign or onboarding a new sending domain. For ongoing campaigns, the weekly maintenance check covers items 1-8 (DNS and content) plus items 20-27 (monitoring and tools). Any item that fails should be fixed before sending another batch.
For the day-by-day warmup schedule referenced in item 15, see the 14-day domain warmup protocol. For a deeper dive into any spam placement issues uncovered during your check, the 17 root causes of spam placement guide provides detailed diagnostics for each issue.
When monitoring reveals bouncing issues (item 20), use the bounce rate benchmark data to determine whether your rates are within acceptable range for your industry. For reply rate optimization (item 22), the reply rate optimization playbook provides specific tactics to improve engagement.
The cost of skipping deliverability checks
A back-of-napkin calculation: if you send 100 cold emails per day and 40% go to spam (common without proper setup), you are wasting 40 sends per day. At an average reply rate of 3.43% (Instantly 2026 Benchmark Report), those 40 lost emails represent 1.4 missed replies per day, or roughly 30 missed conversations per month. If your close rate is 10% and average deal value is $2,000, that is $6,000 in lost revenue per month from poor deliverability alone.
The checklist takes 30-60 minutes to complete for a new domain. For the broader cold email strategy that wraps around this technical foundation, see the B2B Cold Email Guide for 2026 and the Email Deliverability Mastery pillar.
Frequently asked questions
What is a good deliverability rate for cold email?
A good inbox placement rate for cold email is 85% or higher, meaning 85 out of 100 emails land in the primary inbox rather than spam or promotions. Top performers achieve 92-95% inbox placement. Below 80% indicates a significant deliverability problem that will suppress reply rates and waste send volume. Monitor inbox placement weekly, not just open rates — open rates alone do not distinguish inbox from promotions tab delivery.
How often should I run a deliverability check?
Run the full checklist before launching any new campaign or onboarding a new sending domain. Run a simplified version (items 1-8 and 20-27) weekly during active campaigns. Run an emergency audit immediately if bounce rates exceed 3%, reply rates drop by 50%+, or you receive a blacklist notification. Consistent monitoring prevents small issues from becoming permanent reputation damage.
What is the most important deliverability factor?
DNS authentication (SPF, DKIM, DMARC) is the single most important factor. Without all three properly configured, inbox providers will reject or spam-filter your emails regardless of content quality or sending behavior. After authentication, sender reputation (built through warmup and engagement signals) is the second most impactful factor. Content optimization comes third.
Can I improve deliverability without buying tools?
Yes. The majority of this checklist can be completed with free tools: MXToolbox for DNS checks, Mail-Tester.com for email scoring, Google Postmaster Tools for Gmail-specific reputation data, and your ESP dashboard for bounce and complaint rates. Paid tools like GlockApps ($59/month) and email verification services ($15-50/month) add efficiency but are not strictly required for small-volume senders.
Related reading: 14-day domain warmup protocol · Why cold emails go to spam (17 causes) · Cold email software comparison