IP and Domain Warmup for Email: a 30-Day Plan

Why you warm up an IP and domain

IP warmup for email campaigns is the gradual ramp-up of volume from a new IP address and domain so mailbox providers build a positive reputation. Send a large volume from a "clean" IP right away and Gmail and Outlook read it as a spam attack — blocking you or filing you in spam. Below is a 30-day plan with a daily volume table.

Core principle: ramp by achievement, not by calendar

Grow volume by metrics, not mechanically "by day". Move to the next step only if the previous one held:

• Spam complaints under 0.1%.
• Hard bounces under 2%.
• Open rate above 20% (a sign of engagement).
• Domain reputation in Google Postmaster Tools at High/Medium.

If metrics dip, stop and hold volume until you fix the cause.

Start with the most engaged

For the first 1–2 weeks, mail only people who opened in the last 30–90 days. Their opens and clicks give the provider a strong positive signal. Bring the cold part of your list in last.

30-day volume table

This is a guide. For a small list use smaller steps; for a large one you can ramp faster — always watching the metrics.

Separate your mail streams

Warm transactional mail (passwords, receipts — high open rate) separately from marketing. Ideally on different subdomains:

mail.example.com   — marketing
tx.example.com     — transactional

That way reputation trouble on promo campaigns will not hurt delivery of critical mail.

Domain warmup and IP warmup are not the same

Separate the two jobs. Domain reputation is built on authentication and recipient behavior and follows you across servers. IP reputation is tied to a specific address. On a dedicated IP you fully control reputation but must keep a steady volume: send rarely or in bursts and the address "cools off". On a shared IP the IP warmup is already done for you by the provider — but then it is the domain you need to warm. For smaller volumes (up to ~50k/month) a shared IP is usually the better choice.

Keep a steady rhythm

Providers value predictability. It is better to send a little every day than one big burst once a week. Fix a schedule (for example weekdays at the same time) and do not swing more than roughly 2x day to day. Sharp volume "swings" read as an anomaly to the provider.

What to monitor daily

1. Google Postmaster Tools — domain/IP reputation, spam rate, authentication.
2. Outlook SNDS — for Microsoft mailboxes.
3. Blocklists — Spamhaus, to catch a problem early.
4. Your own stats — bounces, complaints, opens, unsubscribes.

Common warmup mistakes

• Skipping days: reputation "cools off" — ramp gently again after a pause.
• Starting on a cold list — a guaranteed failure.
• Ignoring authentication: without SPF/DKIM/DMARC, warmup is pointless.
• A sudden spike "because the sale is on" — resets the whole warmup.

Bottom line

What to send during warmup

Warmup is about content as much as volume. In the first weeks send what people will surely open: welcome emails, confirmations, useful digests. Avoid aggressive promos, heavy images and dozens of links — they raise your spam score while reputation is still fragile. One or two links to your main domain, clean HTML, a clear subject with no caps or emoji — that earns the high opens that drive warmup forward.

Warmup mini-FAQ

How long does warmup take?

Usually 3–6 weeks to reach full volume. Large and cold lists take longer.

Can I speed it up?

Only through engagement: the higher your opens and clicks, the faster the provider raises limits. You cannot mechanically jump volume.

Do I need to warm up when changing ESP or server?

If the sending IP changes — yes, IP reputation is tied to the address. Domain reputation persists, so the re-warmup is shorter than the original.

What if reputation drops during warmup?

Step back on volume, mail only your most active users, and do not ramp until metrics recover.

Warmup is a 3–6 week marathon where metrics beat the calendar. Set up authentication (see the DMARC guide), start with active users, ramp by achievement and watch the postmasters. Automating a smooth ramp and subdomain split is easy with the YourTrend API and SMTP, and you can verify readiness in the YourTrend lab.