Cold email deliverability is not a one-time setup task. It is an ongoing operating discipline. This checklist covers every variable that affects whether your emails land in the primary inbox or disappear into spam. Use it before every new campaign launch and as a monthly audit for active programs.
Domain and sending infrastructure
- ✓ SPF record configured on every sending domain
- ✓ DKIM signing enabled and verified for each inbox provider
- ✓ DMARC policy set to at least p=none with a monitoring email address
- ✓ Secondary sending domain in use — never send cold outreach from your primary company domain
- ✓ Domain age is at least 2 weeks before any sending begins
- ✓ Domain has a matching website — a live page at the root domain reduces spam scoring
- ✓ MX records are configured so replies land correctly
Inbox warmup
- ✓ Warmup duration: minimum 3 weeks (4 weeks recommended for new domains)
- ✓ Warmup volume ramp: start at 10–20 per day, increase by 5–10 per day each week
- ✓ Warmup tool or manual process in place throughout the warm-up period
- ✓ Positive engagement signals during warmup: opens, replies, and moved-from-spam actions help build reputation
- ✓ No cold outreach sent during warm-up period — warmup and production sends on the same inbox hurt both
List quality
- ✓ Every contact email verified before import using a real-time verification tool
- ✓ Bounce rate below 3% — if not, audit the list source and re-verify
- ✓ No role-based addresses (info@, hello@, support@) — these often hit spam traps
- ✓ Suppression list active — unsubscribes, previous bounces, and opted-out contacts removed
- ✓ List segmented by ICP tier — do not mix high-priority and low-priority contacts in the same sequence
- ✓ Data recency confirmed — contacts sourced more than 6 months ago should be re-verified
Sending behavior
- ✓ Daily send cap per inbox: maximum 100 (50 is safer for newer domains)
- ✓ Send window set to business hours in the recipient's timezone
- ✓ Sending spread across the day — avoid batch sending at the same time, which looks automated
- ✓ Randomized send timing — variable delays between sends improve inbox placement
- ✓ No attachments in first-touch emails — attachments are a major spam trigger
- ✓ Plain text format preferred over HTML for cold outreach
Email content
- ✓ No spam trigger words — check every email with a spam words checker before sending
- ✓ No more than one link per email — multiple links are a spam signal
- ✓ Unsubscribe option included — required under CAN-SPAM and GDPR
- ✓ No misleading subject lines — deceptive subjects trigger spam complaints
- ✓ Personalization tokens tested — broken merge fields ("Hi ,") destroy credibility and can hurt deliverability
- ✓ From name matches a real person — "John at SalesOutreach" outperforms "SalesOutreach Team"
Ongoing monitoring
- ✓ Bounce rate monitored weekly — pause campaigns if it exceeds 3%
- ✓ Spam complaint rate below 0.1% — Google Postmaster Tools tracks this
- ✓ Google Postmaster Tools configured for every sending domain
- ✓ Reply sentiment tracked — rising "not interested" rates signal message-market fit problems
- ✓ Sender reputation checked monthly using MXToolbox or similar tools
- ✓ Active sequences paused if domain health degrades — do not push through warning signs
Before every new campaign launch
- ✓ List verified in the last 30 days
- ✓ Spam words check completed on all emails in the sequence
- ✓ Personalization tokens tested with a real sample send
- ✓ Sending domain health checked (no blacklist flags)
- ✓ Suppression list updated with recent unsubscribes and bounces
- ✓ Campaign owner confirmed and monitoring schedule set
Consistent deliverability is not about luck — it is about operating discipline. Teams that check these items before every campaign and review their domain health weekly will outperform teams that treat deliverability as a one-time setup for years. Start with the spam words checker and the cold email grader to score any email before it goes live.
FAQ
What is the most common cause of cold emails going to spam?
In our experience auditing outbound campaigns, the most common causes are: sending from a domain with no SPF/DKIM/DMARC setup, using an unverified list with high bounce rates, and including spam trigger words or multiple links in the email body.
Related guide: cold email deliverability tool
How often should I check my domain sender reputation?
Monthly at minimum. If you are actively sending campaigns, check weekly. Set up Google Postmaster Tools for any domain that sends more than 100 emails per day — it gives you real spam complaint rate data from Gmail directly.
Can I send cold email from my main company domain?
Technically yes, but it is not recommended. If the sending domain gets flagged or blacklisted, it affects your main company email too. Use a secondary domain (e.g., trycompanyname.com or outreach.companyname.com) and keep your primary domain protected.