Cold Email Deliverability Checklist: 20 Things to Check Before Every Campaign
Cold email deliverability is the single biggest factor determining whether your outbound campaigns succeed or fail. You can write perfect copy, target the ideal prospects, and have a compelling offer, but if your emails land in spam, none of it matters. This cold email deliverability checklist covers the 20 things you must verify before launching any campaign. At Alchemail, we run through this checklist on every client engagement, and it is a core reason our campaigns maintain 40-60% open rates and 90%+ inbox placement.
Domain and Authentication (Items 1-5)
1. SPF Record Is Configured Correctly
What to check: Every sending domain has an SPF record that authorizes your email sending service (Google Workspace, Microsoft 365, or your sending tool's servers).
How to check: Use MXToolbox SPF Lookup. Enter your domain and verify the SPF record exists and includes the correct "include" statements for your sending provider.
Common mistake: Having multiple SPF records on the same domain. You can only have one SPF record per domain. If you need to authorize multiple services, combine them into a single record.
| Status | Action |
|---|---|
| SPF record present and correct | Proceed |
| SPF record missing | Add before sending any emails |
| Multiple SPF records | Merge into one record |
| SPF record exceeds 10 DNS lookups | Simplify by removing unused includes |
2. DKIM Is Enabled and Verified
What to check: DKIM signing is active on every sending account. DKIM adds a cryptographic signature to your outgoing emails that receiving servers use to verify the message was not altered in transit.
How to check: Send a test email to mail-tester.com and review the DKIM section. Or use MXToolbox DKIM Lookup with the appropriate selector for your provider.
Common mistake: Enabling DKIM in your email provider's settings but not adding the DNS records. Both steps are required.
3. DMARC Policy Is Published
What to check: A DMARC record exists on every sending domain. At minimum, set the policy to "none" (monitoring mode). For maximum deliverability, move to "quarantine" or "reject" over time.
How to check: MXToolbox DMARC Lookup. The record should look like: v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com
Recommended progression:
- Month 1:
p=none(monitor only) - Month 2:
p=quarantine(spam suspicious emails) - Month 3+:
p=reject(block unauthorized emails)
For a complete authentication setup guide, see our SPF, DKIM, and DMARC guide.
4. Sending Domains Are Not Your Primary Domain
What to check: You are NOT sending cold emails from your main company domain. Cold emails should always go from separate, dedicated sending domains.
Why: If cold email activity generates spam complaints (inevitable at scale), it damages the sending domain's reputation. Using separate domains isolates this risk from your primary business email.
Best practice: Use domain variations of your brand. If your company is acme.com, use tryacme.com, getacme.io, acmehq.com, etc. Register 100+ domains for campaigns at scale.
5. Domains Are Aged Appropriately
What to check: Sending domains are at least 14 days old before starting warmup, and at least 30 days old before sending campaign emails.
Why: Brand-new domains have zero reputation. Email providers are suspicious of new domains sending bulk email. Aging domains (even just 2-4 weeks) before using them helps establish baseline reputation.
| Domain Age | Status |
|---|---|
| 0-14 days | Too new, do not use yet |
| 14-30 days | Ready for warmup |
| 30+ days (with warmup complete) | Ready for campaigns |
Warmup and Reputation (Items 6-10)
6. Email Accounts Are Fully Warmed
What to check: Every sending account has completed a minimum 14-21 day warmup period before any campaign emails are sent.
How to verify: Check your warmup tool (SmartLead, Instantly, or similar) dashboard. Each account should show 30+ warmup emails sent and received per day with positive engagement signals.
Common mistake: Cutting warmup short because you are eager to start campaigns. Sending campaigns from partially warmed accounts leads to immediate deliverability problems.
7. Warmup Is Running Continuously
What to check: Warmup continues to run on all sending accounts even after campaigns start. Do not pause warmup when you begin sending campaigns.
Why: Continuous warmup maintains sender reputation by ensuring a steady stream of positive engagement signals alongside your campaign emails. The ratio of warmup-to-campaign emails should be at least 1:1.
8. Inbox Placement Rate Is Above 90%
What to check: Before launching campaigns, send test emails to seed accounts and verify inbox placement is above 90%.
How to check: Use GlockApps, Mail-Tester, or your sending tool's built-in deliverability testing. Send test emails to a mix of Gmail, Outlook, and Yahoo addresses.
| Inbox Placement | Action |
|---|---|
| 95%+ | Excellent, proceed with campaigns |
| 90-95% | Good, proceed but monitor closely |
| 80-90% | Investigate and fix before campaigns |
| Below 80% | Do NOT send campaigns, diagnose issues |
9. Sending Volume Ramp Is Planned
What to check: You have a plan to gradually increase sending volume over the first 5-7 days of campaigns, not start at full volume immediately.
Recommended ramp:
- Day 1-2: 10-15 emails per account
- Day 3-4: 15-20 emails per account
- Day 5-7: 20-25 emails per account
- Day 8+: Full volume (25-30 per account)
10. Blacklist Status Is Clean
What to check: None of your sending domains or IPs appear on major email blacklists.
How to check: MXToolbox Blacklist Check. Test each sending domain.
If blacklisted: Do not use that domain until the listing is resolved. Most blacklists have a removal process, but it can take 7-14 days.
List Quality (Items 11-14)
11. Every Email Address Is Verified
What to check: 100% of email addresses in your campaign have been verified through a dedicated email verification service (LeadMagic, NeverBounce, ZeroBounce, etc.).
Target bounce rate: Under 2%. Lists with bounce rates above 3% indicate insufficient verification and will damage your sender reputation.
| Bounce Rate | Assessment |
|---|---|
| Under 1% | Excellent |
| 1-2% | Acceptable |
| 2-3% | Needs attention |
| Above 3% | Do not send, re-verify list |
12. Role-Based and Catch-All Emails Are Handled
What to check: Role-based emails (info@, sales@, support@, contact@) are excluded from campaigns. Catch-all domains (domains that accept all emails regardless of the recipient) are flagged and handled carefully.
Why: Role-based emails rarely reach individual decision-makers and often trigger spam filters. Catch-all emails verify as "valid" but may not exist, leading to hidden bounces.
Best practice: Exclude role-based emails entirely. Include catch-all emails only if the domain is high-value and you have confidence the contact exists from another source.
13. Suppression Lists Are Applied
What to check: Your campaign excludes:
- Previous opt-outs and unsubscribes
- Existing customers
- Current active prospects in your pipeline
- Contacts who bounced in previous campaigns
- Competitors
- Any domain-level exclusions (e.g., government domains, educational institutions)
14. List Is Recent
What to check: Contact data is no more than 30 days old. Email addresses change frequently: people switch jobs, companies restructure, domains expire.
Best practice: Verify emails within 7 days of sending. Data older than 30 days should be re-verified before use.
Email Content (Items 15-18)
15. No Spam Trigger Words in Subject Lines
What to check: Subject lines do not contain words or patterns that trigger spam filters.
Words and patterns to avoid:
- "Free," "Guarantee," "No obligation"
- ALL CAPS
- Multiple exclamation marks
- Dollar signs or specific price mentions
- "Act now," "Limited time," "Urgent"
Best subject lines for cold email: Short (3-5 words), specific to the prospect or their company, and curiosity-driven.
16. Minimal Links and No Images
What to check:
- Email 1: Zero links (or one link maximum)
- Follow-up emails: One link maximum
- No images in any cold email
- No HTML formatting (bold, colors, tables)
- No link shorteners (bit.ly, etc.)
Why: Links, images, and HTML formatting are strong spam signals in cold email. Every additional link increases the probability of spam filtering.
17. Unsubscribe Mechanism Is Included
What to check: Every email includes a way for the recipient to opt out. This can be:
- An unsubscribe link (most sending tools add this automatically)
- A text-based opt-out: "If this is not relevant, reply 'remove' and I will take you off the list"
Legal requirement: CAN-SPAM requires a clear opt-out mechanism in commercial emails.
18. Plain Text Format
What to check: Emails are sent in plain text, not HTML. They should look like a normal email someone typed in Gmail, not a marketing newsletter.
Checklist:
- No images
- No colored text
- No styled buttons
- No custom fonts
- Simple email signature (name, title, company, phone)
- No banner images in signature
Monitoring and Safety (Items 19-20)
19. Monitoring Dashboard Is Set Up
What to check: You have a system to monitor the following metrics daily (at least weekly):
- Open rates by domain and campaign
- Reply rates by domain and campaign
- Bounce rates by domain
- Spam complaint rates by domain
- Inbox placement (via periodic testing)
- Warmup health for all accounts
Red flags to watch for:
- Open rate drops below 30% on any domain
- Bounce rate exceeds 3% on any campaign
- Spam complaints exceed 0.1%
- Inbox placement drops below 85%
When any red flag triggers, immediately pause campaigns from the affected domain or account, investigate, and fix before resuming.
20. Backup Domains Are Warming
What to check: You have 10-20% extra domains and accounts in warmup as reserves. If an active domain underperforms and needs to be pulled, you can swap in a warmed reserve without interrupting campaign volume.
Example: If you are running 100 active domains, have 10-20 domains warming in the background at all times.
For a comprehensive guide on maintaining deliverability over time, see our cold email deliverability guide.
The Quick-Reference Checklist
Print this or save it. Run through it before every campaign launch:
| # | Check | Status |
|---|---|---|
| 1 | SPF configured on all sending domains | |
| 2 | DKIM enabled and verified | |
| 3 | DMARC policy published | |
| 4 | Not sending from primary company domain | |
| 5 | Domains aged 30+ days | |
| 6 | All accounts completed 14-21 day warmup | |
| 7 | Warmup running continuously | |
| 8 | Inbox placement above 90% | |
| 9 | Sending volume ramp planned | |
| 10 | No domains/IPs on blacklists | |
| 11 | Every email address verified | |
| 12 | Role-based and catch-all emails handled | |
| 13 | Suppression lists applied | |
| 14 | Contact data under 30 days old | |
| 15 | No spam trigger words in subject lines | |
| 16 | Minimal links, no images | |
| 17 | Unsubscribe mechanism included | |
| 18 | Plain text format confirmed | |
| 19 | Monitoring dashboard active | |
| 20 | Backup domains warming |
Frequently Asked Questions
How often should I run this deliverability checklist?
Run the full checklist before every new campaign launch. For ongoing campaigns, check items 8, 10, 11, and 19 weekly. Deliverability is not static; it requires ongoing monitoring.
What is the single most important item on this checklist?
Email verification (Item 11). High bounce rates from unverified lists are the fastest way to destroy sender reputation. Every other deliverability practice becomes irrelevant if your bounce rate is above 3%.
Can I fix deliverability problems mid-campaign?
Yes, but act fast. If you detect issues (dropping open rates, high bounces, spam complaints), pause the affected accounts immediately. Diagnose the root cause, fix it, and resume sending. Do not continue sending from compromised accounts.
How long does it take to recover from a deliverability problem?
Minor issues (one account flagged) can be resolved in 24-48 hours by pausing the account and letting warmup rebuild reputation. Major issues (domain blacklisted) can take 7-14 days to resolve. In severe cases, retiring the domain and deploying a fresh one is faster than rehabilitation.
Do I need to run this checklist for every domain individually?
For items 1-5 (authentication), yes. Every domain needs its own SPF, DKIM, and DMARC records verified individually. For other items, you can check at the campaign level and spot-check individual domains.
Need help setting up or auditing your cold email deliverability? Book a call with Alchemail and we will review your setup.