Most cold email campaigns fail before anybody reads a word. The message goes to spam, the sender sees low reply numbers and blames the copy, and they spend a month rewriting emails nobody was ever going to see.
Here is the setup we use, in the order we do it.
Never send from your main domain
Buy separate domains for sending. If your company is acme.com, you might send from getacme.com or acmehq.com. Point each one at your real website so anyone who types it in lands on your site.
The reason is simple: reputation attaches to domains. If a sending domain gets flagged, you retire it and buy another. If your main domain gets flagged, your proposals, invoices and customer email start landing in spam, and that is a much worse month.
Use .com where you can. Unusual endings look odd to readers, and some filters treat them with more suspicion.
Keep inboxes per domain small
It is tempting to put ten inboxes on one domain and send from all of them. Then one bad week damages all ten at once. A small number per domain, often two or three, spreads the risk and keeps each domain's sending pattern looking like a real small team.
Buy more domains when you need more volume. They are cheap compared with what they protect.
Set up SPF, DKIM and DMARC
These three DNS records prove you are allowed to send as that domain.
- SPF lists which servers may send for the domain.
- DKIM adds a signature that shows the message was not altered on the way.
- DMARC tells receivers what to do when the first two fail, and where to send reports.
Since 2024, Google and Yahoo have required authentication from anyone sending in bulk, along with a spam complaint rate below 0.3 percent and easy unsubscribes. Microsoft brought in similar requirements for Outlook consumer addresses in 2025. Even if you are well below their bulk thresholds, behave as if they apply to you, because these are the signals filters use for everyone.
Check the records with a free lookup tool before you send a single message. A typo in a DNS record can sit unnoticed for months.
Warm up every inbox
New inboxes have no history, and no history looks suspicious. Warmup tools exchange ordinary looking email between inboxes, opening them and marking them as important, which builds a track record. Two weeks is a sensible minimum before real sending. Some people run shorter warmups and get away with it. The downside of going too fast is a burned domain, and the downside of going slowly is a few days.
Then leave warmup running during your campaigns. Turning it off once you launch is one of the most common reasons a setup that worked in month one falls apart in month two.
Ramp volume in steps
Start at around 10 emails per inbox per day. Move to 15, then 20, then 30 over about two weeks, watching the numbers as you go. Do not jump because you are impatient. Thirty a day from each inbox is a comfortable ceiling for most setups, and if you need more volume, add inboxes and domains and leave the limit alone.
Turn tracking off
Open tracking adds a tiny image to each email. Link tracking rewrites your links through a shared domain. Both make your plain email look like marketing email, and both can hurt delivery. Open rates have also been unreliable for years because of how mail apps load images. Measure replies, which is the number that pays you anyway.
Verify every address
Bounces do more damage than most people realize. Run every list through an independent verifier and keep only the addresses it confirms as valid. If you are buying from a data provider, verify anyway, because a lot of their records are stale.
Set a hard rule: any campaign over 3 percent bounces stops automatically until you know why.
Know what the numbers are telling you
- Bounce rate climbing: your list is stale or verification got skipped. Pause now.
- Replies near zero from a healthy setup: usually the wrong audience. Check the list before you touch the copy.
- Hostile replies: your targeting is off. These turn into spam complaints, and complaints compound.
- Strong results that slowly fade: check whether warmup got turned off, and test inbox placement.
None of this is secret. It is just unglamorous work that has to be done before the interesting part, and it keeps getting done wrong because nobody can see it. If you would rather not run it yourself, this is exactly what we set up for clients.
