The deliverability guide for people who send cold email for a living.
Deliverability isn't a feature. It's an engineering discipline. This guide covers everything that determines whether your email hits the inbox or the spam folder.
Why deliverability is the only metric that matters
You can write the perfect cold email, target the perfect ICP, and build a perfect sequence. None of it matters if the email lands in spam. Deliverability is the foundation of every cold email campaign. It's determined by your domain reputation, authentication setup, sending patterns, content signals, and recipient engagement. Most teams treat it as a one-time setup. The teams that get results treat it as an ongoing discipline.
What's in this guide
- DNS authentication explained: SPF, DKIM, DMARC setup and verification
- Domain reputation: how it's built, what damages it, and how to monitor it
- Sending patterns: volume ramp, send timing, throttling, and rotation
- Content signals: spam trigger words, link ratios, HTML vs. plain text
- Recipient engagement: how opens, replies, and complaints affect placement
- Inbox provider behavior: how Gmail, Outlook, and Yahoo filter differently
- Monitoring tools: seed testing, blocklist scanning, reputation dashboards
- Recovery playbook: what to do when deliverability drops
Where to go from here
This guide gives you the knowledge to diagnose and fix deliverability issues. For domain-specific warmup instructions, see our Domain Warmup Guide. For infrastructure setup, see our Email Infrastructure Guide. For content optimization, check our Spam Trigger Words reference. Or let us manage deliverability for you -- it's literally what we do all day.
Frequently asked questions
How do I know if I have a deliverability problem?
If your open rates are below 40% (accounting for Apple MPP inflation), your reply rates are below 1%, or you're seeing bounce rates above 5%, you likely have a deliverability problem. Seed testing is the only way to know for sure.
Can I fix deliverability myself?
Yes, if you have the technical knowledge. DNS setup, warmup protocols, and monitoring are learnable. The challenge is maintaining it at scale -- it's a daily discipline, not a one-time fix.
How long does it take to recover from bad deliverability?
Depends on the severity. Minor reputation damage can be fixed in 1-2 weeks. Burned domains need to be retired and replaced (3-4 weeks for new domain warmup). Blacklisted IPs can take days to weeks for removal.
Let us handle deliverability.
Book a call and get a free deliverability audit on your current sending infrastructure.