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Warming up a domain

A brand-new domain (or one that hasn’t sent in 6+ months) carries no sender reputation. Mailbox providers treat sudden volume from an unknown domain as suspicious — usually delivering to spam, sometimes blocking outright.

The cure is gradual ramp-up, paired with the kind of mail providers actually want to deliver.

A warm domain has:

  • A history of consistent send volume.
  • A bounce rate under 2%.
  • A complaint rate under 0.1%.
  • Engagement signals from recipients (opens, clicks, replies) — not just delivery confirmations.

Mailbox providers (Google, Microsoft, Yahoo) score domains on the above and adjust inbox placement accordingly.

DaySend volumeAudience
1100Most engaged — past openers / clickers only
2250Same
3500Add recently-active subscribers
41,000Same
52,500Add the rest of valid contacts
65,000Full audience mix
710,000
8+Double daily until you hit your target

Throughout: keep bounce rate under 2% and complaint rate under 0.05%. If either spikes, hold volume flat for 2–3 days before continuing.

The goal is engaged mail. Order matters:

  1. Internal seeds first — your team, vendors, anyone who’ll definitely open.
  2. Most engaged subscribers — people who’ve opened or clicked in the last 30 days from another domain.
  3. General active — opened in the last 90 days.
  4. Long-dormant — last.

Don’t include “valid but unverified” contacts in the first week — they’re more likely to bounce or never engage.

These are separate:

  • IP warm-up — handled automatically by 3AVA Mail’s warmup orchestrator. New IPs ramp from 50/day to 100k/day over ~25 days.
  • Domain warm-up — handled by you, by sending the right volumes to the right audiences over the first 2–3 weeks.

If both your IP and your domain are new, run both warm-ups in parallel — but stay at the lower of the two daily caps.

Warming a mail.acme.com subdomain is faster than warming acme.com because the root domain often has positive corporate-mail history that anchors the subdomain’s initial reputation. See Subdomain vs root domain.

  • Sending 50,000 from day 1. Even with a “warm” IP, providers don’t trust unknown domains at that volume.
  • Including dormant subscribers early. Dead addresses bounce; semi-dead ones don’t engage. Both hurt warm-up.
  • Skipping seeds. Without engaged opens/replies in the first week, providers have no positive signal to balance against complaints.
  • Throttling too slowly. Stretching warm-up across 6 weeks doesn’t add safety — it just delays you. The schedule above is the right pace.