We build the cold-email engine we wished we had.
We sent cold email for our own products for years, on tools that rented us the mailboxes, billed warmup as an add-on, and then reported an open rate as if it were revenue. When a domain got burned, it was our domain, not theirs.
ColdEngine is the version we wanted. You send from the inboxes you already own, warmup is included on every plan and starts on day one, and every reply comes back to one inbox with the read the AI gave it.
Four things, in order.
They are numbered because they are not equal. When two of them pull in different directions, the lower number wins.
Replies, not vanity metrics
An open rate flatters everyone and proves nothing. A campaign here ends on one line: sent, replied, meetings booked. The Unibox sorts every answer into Lead, Interested, Meeting booked or Not interested, so you can see which of the three is actually moving.
Sending you can stand behind
You connect mailboxes you already own, on domains you already own, over OAuth or plain IMAP and SMTP. Warmup runs from the first day on every plan, never as an upsell, and every step of a sequence shows its spam risk before it leaves.
Built for operators
Founders, agencies and small sales teams who run the sending themselves. That is why mailboxes and emails are unlimited on every plan, and why credits only cover the parts that cost us money: finding leads and the AI agents.
Customer-funded, not VC-funded
No investors to keep entertained, so no growth target that turns an included feature into an add-on. Customers pay the bills. That is why warmup stays in the plan, why you can cancel any time, and why 14 days money back applies to all of them.
Write to the right address.
Every address below reaches a person who works on the product. There is no queue to pass through first.