To warm up a new email domain or IP, set up SPF, DKIM and DMARC first, then send small volumes to your most engaged contacts and increase gradually over several weeks. Google warns that doubling volume at once can trigger rate limiting. Watch bounces, complaints and Postmaster Tools, and slow down at the first sign of trouble.
This guide explains when you need a warm-up, what to set up beforehand, a sample schedule, the warning signs to watch for, and the mistakes that undo the work.
Key takeaways
- Set up SPF, DKIM and DMARC before sending, then start with small volumes to your most engaged contacts.
- Increase volume gradually over several weeks, as Google warns that doubling volume at once can trigger rate limiting.
- Watch bounces, deferrals and your Postmaster Tools spam rate, keeping it below 0.3% and ideally below 0.1%.
- Never import an old or purchased list during warm-up, as dead addresses and spam traps undo weeks of work.
What does "warming up" an email domain mean?
Mailbox providers such as Gmail, Outlook.com and Yahoo judge mail partly on the sender's history. A brand-new domain or IP has no history, so receivers treat it cautiously. Warming up means building a track record deliberately: modest, consistent volume to people who open and reply, so the first data receivers collect about you is good.
Google's sender guidelines put it plainly: increase volume slowly, send at a consistent rate, avoid bursts, and start with engaged users.
Do I need to warm up my domain, my IP, or both?
It depends on how you send.
| Situation | Warm the domain? | Warm the IP? |
|---|---|---|
| New domain on Google Workspace or Microsoft 365, normal staff email | Light touch: just send normally and build up | No, the provider owns the IPs |
| New domain on a marketing platform's shared IPs | Yes | No, the platform manages shared IP reputation |
| Dedicated IP from your email platform | Yes | Yes |
| Your own mail server | Yes | Yes |
| Existing domain, new sending platform | Partly: ramp the new stream separately | If the IP is new |
Domain reputation travels with you between platforms; IP reputation stays with the IP. For most small businesses on shared infrastructure, domain warm-up is the part that matters.
What should I set up before sending anything?
Get the technical basics right first, because early failures count against you.
- SPF listing every service that sends as your domain. Use our SPF record generator if you're starting fresh.
- DKIM signing on every platform, with a 2048-bit key where supported (Google requires at least 1024 bits for bulk senders).
- DMARC at
p=nonewith a reporting address, so you can see who is sending as you. Our DMARC record generator builds one. - Reverse DNS (PTR) on any dedicated IP, resolving back to the same IP.
- A real website on the domain, with a working contact page and privacy policy (our privacy policy generator can produce a first draft). A domain that resolves to nothing looks suspicious.
- Consistent From details. Use the same From name and address throughout the warm-up.
- Feedback loops and monitoring. Verify your domain in Google Postmaster Tools and register IPs with Microsoft SNDS if you have dedicated ones. Agencies warming several client domains can use MakeItFlow's bulk audits to check every domain's records at once.
MakeItFlow can confirm the DNS side in one pass: run a free website audit and check the email section for MX, SPF, DKIM, DMARC, MTA-STS and BIMI results.
What does a good warm-up schedule look like?
No provider publishes an official schedule, and the right pace depends on your list quality and how much you eventually need to send. The plan below is an illustrative starting point for a domain that will eventually send around 10,000 marketing emails a week. It increases by well under double at each step, in line with Google's warning about doubling volume.
| Week | Daily volume (approx.) | Who to mail |
|---|---|---|
| 1 | 50–100 | Customers and contacts who opened or clicked in the last 30 days |
| 2 | 150–250 | Engaged in the last 60 days |
| 3 | 300–500 | Engaged in the last 90 days |
| 4 | 600–900 | Add recent sign-ups |
| 5 | 1,000–1,500 | Wider active list |
| 6+ | Full volume, spread across days | Whole consented list, minus long-term inactives |
Practical rules:
- Spread sends out. Send through the day rather than all at 9am, and avoid one huge weekly blast.
- Keep the cadence steady. Daily or several times a week beats sporadic bursts.
- Ramp each new stream separately. Google advises that when you change infrastructure or email format, you increase the changed traffic separately.
- Make early emails worth opening. Welcome series, order updates and useful content earn opens and replies.
How do I know if the warm-up is going wrong?
Watch these signals every day during the first month:
- Temporary deferrals (4xx codes). Gmail's
421 4.7.28means it has spotted unusual volume and is rate limiting you. Google says to stop sending for at least 10 minutes, then resume from a single connection and add connections one at a time. - A rising hard-bounce rate. Lots of "user unknown" bounces is a sign of an old or bought list.
- Spam rate in Postmaster Tools. Google requires bulk senders to stay below 0.3% and recommends below 0.1%.
- Opens dropping at one provider only. Often means you're landing in junk there.
- Blocklist listings. Look up your sending IP and domain at check.spamhaus.org if bounces mention a blocklist.
If any of these appear, Google's guidance is to reduce volume until errors fall, then increase slowly again.
What mistakes ruin a warm-up?
- Importing an old or purchased list. Dead addresses and spam traps undo weeks of work in a day. Run older contacts through an email address checker to weed out typos and dead domains first.
- Jumping straight to full volume because a campaign deadline is looming.
- Changing domains to "escape" bad reputation. Receivers link domains through shared IPs, content and links, and new domains often face stricter treatment.
- Using a cold-outreach tool's automated "warm-up network" as a substitute for real engagement. These systems generate artificial opens and replies between mailboxes; they don't replace mail people actually want.
- Skipping authentication on one of your platforms, so part of your mail fails DMARC alignment.
Frequently asked questions
How long does email warm-up take?
Plan for four to eight weeks for a new domain sending marketing volume, longer for a dedicated IP aiming at high volume. Low-volume business email on Google Workspace or Microsoft 365 needs little formal warm-up; just avoid mass mailing from day one.
Can I send newsletters from a domain I registered last week?
You can, but start small. A brand-new domain with no history and an immediate large send is a classic spam pattern. Ideally register the domain, set up the website and authentication, and use it for normal email for a few weeks first.
Should I use a subdomain for marketing email?
Many businesses send marketing from a subdomain such as news.example.com to keep it apart from staff and transactional mail. It still needs warming up, and Google counts subdomain mail towards your primary domain's bulk-sender total, so it isn't a way around the rules.
Do I need to warm up again after a break in sending?
If you stop sending for a month or more, restart gradually with your most engaged contacts. Receivers weigh recent behaviour, and a sudden large send after silence looks like a compromised or bought list.
Does warming up apply to cold email outreach?
The same principles apply, but cold email carries extra risk because recipients didn't ask for it, so complaint rates are higher. Check the law where your recipients are before emailing people who haven't opted in: PECR and UK GDPR in the UK, CASL in Canada, and CAN-SPAM in the US, which doesn't require prior consent but does require accurate sender details, a physical postal address and a working opt-out.
What to do next
Check your SPF, DKIM and DMARC are in place before your first send, verify the domain in Google Postmaster Tools, and pull together a list of contacts who've engaged in the last 30 days to start with. Then follow the Gmail, Yahoo and Microsoft sender requirements so you're compliant before volume grows, and use our email authentication checklist to catch anything you missed.
Related reading
- How Email Blacklists Work: DNSBL Lookups, IP and Domain Lists: How DNS blocklists work, which IP or domain to check, what return codes like 127.0.0.2 mean, and why shared hosting IPs get listed when you did nothing wrong.
Sources
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We build the website audit these guides are based on. Every fact is checked against the primary sources listed above and this guide was last reviewed on 30 October 2026 . How we research and check
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