Mailbox providers judge new domains cautiously. Send a large campaign on day one and much of it may end up in spam. Warming up means building trust gradually.
Authenticate first
Before anything else, verify the domain with SPF, DKIM and DMARC. Unauthenticated mail starts with a handicap no warm-up can fix.
Start with your best contacts
Send the first campaigns to the people most likely to open and click: recent signups and contacts who engaged in the last 30 days. A segment such as "opened or clicked in the last 30 days" is perfect for this.
Grow volume steadily
Roughly double the number of recipients with each send over a couple of weeks, as long as engagement stays healthy. If bounces or complaints rise, slow down.
Watch the signals
In each campaign report, keep an eye on:
- Bounce rate: high hard bounces mean old or purchased addresses. Clean the list.
- Complaints: even a small share is a warning sign. Make unsubscribing easy and send only what people asked for.
- Click rate: a better health signal than opens, which privacy features inflate.
Keep it up
Reputation decays when you stop sending. A steady rhythm, even if it is just a monthly newsletter, keeps your domain in good standing.