Hlib Storchak · 2026-06-22 · ~9 min readQuick answer
Land in the inbox by treating deliverability as part of the build, not a fix you reach for later. Send cold mail only from dedicated domains, never your main one. Warm those domains for a few weeks first. Set up SPF, DKIM and DMARC before the first send. Keep volume sane, verify every list, and avoid the things that trip filters. Then watch reply rate, because opens lie.
Deliverability is the build, not an afterthought
Most teams treat deliverability as a problem they will deal with when emails start going to spam. By then it is too late. The reputation is already damaged, and reputation is slow to earn and fast to lose.
I build deliverability in from the start, before a single cold email goes out. The infrastructure, the authentication, the warmup and the list hygiene all come first. Done that way, the cold mail lands and your main domain is never put at risk. That last part is the whole point, and it is the thread running through everything below.
I have booked over 2000 meetings for B2B clients, and not one of them came from a domain that was burning. Good copy on a domain that lands in spam books nothing. So the infrastructure comes first.
Send from dedicated domains, never your main one
This is the single most important rule, so it goes first. Cold outreach draws spam complaints. That is simply what happens when you email people who did not ask to hear from you, even when you do it well and target tightly.
Spam complaints damage the reputation of whatever domain sent the mail. If that is your main domain, the one carrying your invoices, your contracts and your team's daily email, one rough stretch can poison all of it. Suddenly your real business mail is landing in spam too, and that is a far worse problem than a quiet campaign.
The fix is to register separate domains used only for cold mail. A common pattern is a close variant of your brand, something like getyourbrand.com or tryyourbrand.com, kept entirely apart from the domain your business runs on. If a sending domain takes a reputation hit, your real email is untouched. That separation is non-negotiable.
Spread sending across a few mailboxes
Inside those domains, do not hammer one address. Use a handful of mailboxes and split the volume across them, with a sane daily cap on each. A few warmed mailboxes sending modest volume each is far safer than one mailbox sending a lot. Use real-sounding sender names too, since an address like rep1@ or info@ reads as a robot to filters and to people.
Warm the domains before you use them
A brand new domain with no sending history looks suspicious to inbox providers. It has no track record, so there is nothing to trust. If you start blasting cold mail from it on day one, you are asking to land in spam.
Warmup fixes this. For a few weeks before any cold mail goes out, the domains build a normal sending pattern: small volumes, real-looking exchanges, replies coming back. This teaches the providers that the domain behaves like a person, not a blast cannon. Most teams run warmup automatically and keep a light version of it running even after campaigns start, so the reputation stays healthy.
Plan for a three week minimum here. There is no shortcut. A domain you warm properly will outperform a rushed one for its entire life.
Authentication: SPF, DKIM and DMARC, explained plainly
These three DNS records prove your mail is really from you. Without them, providers treat your email as unverified, which now means straight to spam or rejected outright. As of 2026, Google, Yahoo and Microsoft all require them. Set all three before your first send. Here is what each one does in plain terms.
| Record | What it is, plainly | Why it matters |
|---|---|---|
| SPF | A list of which servers are allowed to send mail for your domain | Stops anyone else from sending as you, and proves your sender is approved |
| DKIM | A cryptographic signature on each email that proves it was not altered in transit | Confirms the mail genuinely came from your domain and arrived intact |
| DMARC | A policy that tells receivers what to do when SPF or DKIM fail, plus reports on who is sending as you | Ties the first two together and gives you visibility into your own sending |
Think of it as three checks: SPF says the right server sent it, DKIM says it was not tampered with, and DMARC says what to do if either check fails. Start DMARC on a monitoring policy so you can read the reports without bouncing your own mail, then tighten it once everything passes cleanly.
The one-click unsubscribe rule. The big providers now expect a working list-unsubscribe header so recipients can opt out in one click. Add it. It costs you nothing, it keeps you compliant, and an easy unsubscribe is far better for your reputation than someone hitting the spam button instead.
Keep volume sane and ramp it slowly
Even with perfect authentication and warm domains, sending too much too fast looks like spam. Providers watch your pattern, and a sudden spike from a quiet domain is a red flag. The answer is to ramp.
Start low and climb gradually over several weeks. A rough shape looks like this: a handful of sends per mailbox per day at first, climbing slowly until you settle at a modest steady cap. Keeping each mailbox well under a hundred a day, and most run far lower, is what keeps the pattern looking human. If you need more volume, add mailboxes, do not crank one harder.
Why steady beats spiky
Predictable volume builds trust. A domain that sends a similar, modest amount every weekday looks like a working business. A domain that sends nothing for a week then fires a thousand emails looks like exactly what it is. Smooth and steady wins. Resist the urge to push volume the moment a campaign looks promising.
List hygiene: verify before you send
Bounces are one of the fastest ways to wreck a domain. When you email addresses that do not exist, providers read it as a sign you scraped a bad list, and your reputation drops sharply. The big providers want bounces kept low, and going over their threshold suppresses your sending across the board.
The fix is simple and not optional: verify every list before the first send. Run the addresses through a verification tool and remove anything invalid, risky or catch-all. Contact data also goes stale over time as people change jobs, so a list that was clean six months ago is not clean today. Re-verify before you reuse an old one.
Run a small test send first
Before a big send, mail a small batch of verified addresses and wait a day. Check the bounce rate. If it is high on the test, the list is dirty and the full send will be worse, so stop and clean it. This canary step takes an hour and saves a domain. Skipping it is how good infrastructure gets burned by a bad list.
What trips spam filters
Once the infrastructure is right, the content still has to pass. Filters look at the message itself and at how people react to it. A few things reliably cause trouble, and most are easy to avoid.
| Good practice | Deliverability killer |
|---|---|
| One plain, relevant link, or none | Several links, link shorteners, or mismatched URLs |
| Plain text that reads like a person wrote it | Image-heavy mail, tracking pixels and big attachments |
| Short, specific, conversational wording | Spammy words: free, guarantee, act now, risk-free, all caps |
| Tight, well-fit list that gets replies | Broad blasts that get ignored, deleted or marked as spam |
| Verified addresses, low bounce rate | Unverified lists with high bounces and complaints |
| Steady volume from warmed domains | Sudden spikes from a cold or unwarmed domain |
Engagement is a signal too
Filters do not just read your words, they watch what happens after you hit send. Replies and people moving your mail to their inbox are strong positive signals. Deletes without reading, and spam complaints, are strong negative ones. This is why tight targeting and a real offer are part of deliverability, not separate from it. Mail that good-fit people actually want to read keeps your reputation up. Mail blasted at strangers drags it down, no matter how clean your DNS records are.
Keep it short and link-light
Short emails land better than long ones, and not only because people read them. A wall of text, several links and a tracking pixel all add weight that filters notice. A few short sentences, one clear ask and at most one link is both better outreach and better for deliverability. The two goals point the same way here.
Monitor the right signals
The number you watch shapes what you optimise. Watch the wrong one and you will tune toward noise while your real results sit flat.
Open rate is the worst metric to trust. Tracking pixels misfire constantly because of privacy features and spam filters, so the number is often plain wrong, and even when it is right, an open is not interest. People open and forget within seconds.
Reply rate is the reliable signal. It is hard to fake, it ties straight to whether your mail is landing and resonating, and it leads directly to meetings. Watch replies, watch bounces, and watch spam complaints. Those three tell you the truth about your deliverability and your campaign. Opens tell you almost nothing.
Read replies as feedback. Beyond the count, the replies themselves tell you which angle landed and whether your copy felt human. A rising reply rate means your domains are healthy and your message is working. A reply rate that drops while you change nothing is often an early sign of a deliverability problem, so dig in before you assume the copy went stale.
A simple pre-send checklist
Before any campaign goes live, I run down a short list. If every line is a yes, the send is safe. If any line is a no, it waits.
| Check | Ready when |
|---|---|
| Dedicated domains | Cold mail sends only from domains separate from your main one |
| Warmup | Domains warmed for a few weeks and still warming lightly |
| Authentication | SPF, DKIM and DMARC all set and passing |
| Unsubscribe | Working one-click unsubscribe in place |
| List | Every address verified, bounces expected to stay low |
| Volume | Sane daily cap per mailbox, ramping slowly |
| Content | Short, plain, link-light, no spam words |
| Monitoring | Reply rate, bounces and complaints all tracked |
Deliverability and good outbound are the same job
It is tempting to think of deliverability as a technical chore separate from copy and targeting. It is not. A tight list of good-fit accounts gets replies, and replies lift your reputation. A real offer gets engagement, and engagement keeps you in the inbox. Short human copy avoids the spam traps. The things that make outbound work are the same things that keep it landing. Do the outbound well and deliverability mostly takes care of itself, provided the infrastructure underneath is right.
Deliverability across all-bound
Email is the channel where deliverability bites hardest, but it is not the only one I run. I work all-bound: email, LinkedIn and cold calling together, routed to where each buyer actually responds. That matters for deliverability too. Spreading effort across channels means email does not have to carry the entire load, so volume per mailbox stays lower and the domains stay healthier. The channels also reinforce each other, which lifts engagement and, in turn, your sending reputation.
How I set this up
When I build outbound, deliverability is part of the engagement from day one, not a bolt-on. I stand up dedicated domains so your main domain is never touched, warm them properly, configure SPF, DKIM and DMARC, verify every list, keep volume sane and ramp it slowly. Then I run all-bound and report on reply rate and meetings, the numbers that mean something. The whole setup is documented, and it stays yours. If you take it in-house later, you inherit a working system with its reputation intact, not a burned domain and a blank page.
Key takeaways
- Never send cold mail from your main domain. Register dedicated sending domains so spam complaints can never damage your real business email.
- Warm every new domain for at least three weeks before the first cold send — there is no safe shortcut.
- SPF, DKIM and DMARC are non-negotiable. All three must be set and passing before your first send; the major providers now require them.
- Keep daily volume well under a hundred sends per mailbox and ramp slowly over weeks. Add mailboxes for more volume rather than pushing one harder.
- Verify every list before sending and re-verify before reusing an old one — bounces are one of the fastest ways to burn a domain's reputation.
- Watch reply rate, bounces and spam complaints. Open rate is unreliable and tells you almost nothing about deliverability or genuine interest.
FAQ
Can I just send cold email from my normal company domain?
No. Cold outreach draws spam complaints, and those damage whatever domain sends the mail. If that is your main domain, you risk your real business email landing in spam. Always send cold mail from dedicated domains kept separate from the one your business runs on.
How long does domain warmup take?
Plan for at least three weeks before any cold mail goes out, and keep a light warmup running after that. A new domain has no sending history, so providers do not trust it yet. Warmup builds that trust gradually, and there is no safe shortcut.
Do I really need SPF, DKIM and DMARC?
Yes, all three, set before your first send. The major providers now require them, and without them your mail is treated as unverified, which usually means spam or rejection. SPF approves your sender, DKIM proves the message was not altered, and DMARC ties them together with reporting.
How many emails can I send per mailbox per day?
Keep it modest and well under a hundred per mailbox, with most setups running lower. Ramp up slowly over weeks rather than spiking. If you need more volume, add mailboxes and domains instead of pushing a single mailbox harder.
Why should I ignore open rate?
Because it is unreliable and an open is not interest. Tracking pixels misfire thanks to privacy features and spam filters, so the number is often wrong. Reply rate, bounces and spam complaints are the signals that actually tell you whether your mail is landing and working.