You bought a nice domain, set up SPF, DKIM, and DMARC correctly, sent your first thousand emails — and went straight to spam. This is the most common self-inflicted deliverability wound, and it happens because reputation is earned in weeks, not configured in minutes. Here is the warmup process that works, and it is mostly about restraint.
Why new domains get the cold shoulder
Receivers like Gmail and Outlook score senders on history: volume consistency, bounce rates, spam complaints, engagement. A brand-new domain has none of that, and spam operations historically burn through fresh domains fast. So the default posture is suspicion, and the only cure is a track record built gradually. There is no way to buy it or shortcut it; anyone selling one is selling a blacklist ticket.
Use a subdomain for sending
Before you warm anything, decide what domain your mail actually comes from. Transactional mail from mail.yourdomain.com and marketing from news.yourdomain.com keeps reputations separate: a marketing misstep cannot poison your receipts, and vice versa. Authenticate each subdomain with its own SPF and DKIM while the root’s DMARC covers the family. Most providers support this in their domain authentication flow with a couple of extra records.
The four-week schedule
This is the cadence we use for a domain starting from zero, aimed at a steady-state of a few thousand messages a week:
- Week 1: 20–50 messages per day, all to your most engaged people — teammates, existing customers who will open and reply. Engaged opens are the entire game at this stage.
- Week 2: double it, roughly 100 per day. Keep the audience warm; monitor bounces daily.
- Week 3: a few hundred per day. Introduce your regular cadence if you have one.
- Week 4: scale toward your normal volume in increments, never doubling overnight from a cold start.
If you use a shared infrastructure provider, they warm shared IPs for you — your job is still to ramp your domain’s volume and keep engagement high. Dedicated IPs always need their own warmup, and the schedule is the same shape.
Signals to watch, daily
During warmup, check three numbers every morning: bounce rate (keep it under a few percent; above that, pause and clean your list before continuing), spam-complaint rate (should be near zero), and inbox placement on your seed accounts. Your own opens and replies matter more than raw volume — a warmup with great engagement can run twice as fast, and one with silence should slow down.
When it goes wrong anyway
First, do not keep pushing volume — receivers read persistence as spamminess. Diagnose before you scale: confirm authentication with our SPF/DKIM/DMARC guide, check that you are not on a blocklist for the IP you inherited, and cut your list down to people who have engaged in the last ninety days. Rebuild from that core, then expand. A slow, engaged restart fixes most placement problems in two to three weeks; a stubborn blast-through makes them permanent.
Where to start
If you have not picked infrastructure yet, our four-platform field test covers how Mailchimp, SendGrid, Resend, and Brevo handled identical sends, and the Resend tutorial shows the API path from zero. Warmup applies equally whether you use a provider or run your own server — the receivers do not care who built your SMTP stack, only what it has sent lately.