Deliverability
Email warmup: how to land cold emails in the inbox
Great outreach never gets read if it lands in spam. This is the short, non-technical version of everything a sales team needs to warm up a domain and keep it healthy.
What email warmup actually means
Mailbox providers like Gmail and Outlook decide where your message goes based on how people treat your past messages. A new domain has no history, so it starts with no trust. Warmup is the process of building that history on purpose: send a small number of emails, get real replies, and grow the volume slowly until the provider treats you as a normal person rather than a bulk sender.
Two numbers matter more than anything else. Your reply rate, which tells providers people want your email, and your bounce and complaint rate, which tells them the opposite.
Set up the technical basics first
Do these once, before you send anything. Each one is a DNS record your domain provider can add.
SPF. Lists the servers allowed to send email for your domain. Without it, you look forged.
DKIM. Signs every message so the receiver can prove it was not tampered with.
DMARC. Tells providers what to do when SPF or DKIM fails. Start at p=none, then move to quarantine.
Custom tracking domain. Stops your links from sharing a blocklisted shared tracking domain.
A real signature and website. Providers and humans both check that you exist.
A safe four week warmup schedule
| Period | Volume per mailbox | What to watch |
|---|---|---|
| Week 1 | 10–20 emails a day | Only to people who are likely to reply. Answer every reply. |
| Week 2 | 25–40 emails a day | Add your first small cold batch. Keep replies flowing. |
| Week 3 | 50–70 emails a day | Watch bounce rate. Stay under 3%. |
| Week 4+ | 80–150 emails a day | Steady state for one mailbox. Add mailboxes, not volume. |
Send on weekdays, in business hours, spread across the day. A burst of 200 emails at 9:00 looks like a machine. Thirty emails spread over four hours looks like a person.
What sends cold email to spam
- Links in the first email, especially shortened or tracking links
- Attachments in a first touch
- Images or heavy HTML signatures instead of plain text
- Words like free, guarantee, act now, risk free, 100% reply rate
- The same message sent to hundreds of people with no personalization
- Sending from the same domain you use for billing and support
Keeping the domain healthy after warmup
Warmup is not a one-off task. Verify every list before import, remove anyone who does not open after a full sequence, and keep your reply rate above roughly 5%. If replies drop, cut volume in half for a week rather than pushing through. Personalization is the cheapest deliverability tool there is: messages that reference the recipient's actual business get answered, and answers are exactly the signal providers reward.
Email warmup FAQ
How long does email warmup take?
Three to four weeks for a brand new domain and mailbox. If you rush it, mailbox providers file you as bulk mail and it takes months to recover.
Do I need a separate domain for cold outreach?
Yes. Buy a lookalike domain (for example getacme.com next to acme.com) and send cold email only from there. Your main domain keeps its reputation.
How many emails can one mailbox send per day?
Around 80 to 150 after a full warmup. To send more, add more mailboxes, each warmed separately. Never push one mailbox harder.
What bounce rate is safe?
Under 3%. Above 5% and providers start throttling you. Verify every list before you import it.
Warm domain, weak message? Still no replies.
GoodReply reads your prospect's website and writes outreach that references their real situation, so your emails earn the replies that keep your domain healthy.
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