Email warmup basics for new domains

New domains and cold IPs have no reputation. Inbox providers accept small volumes first, then watch engagement and complaints. Warmup is gradual volume increase — not optional for large first sends.

Week 0 — Before first marketing send

• Authentication green (SPF/DKIM/DMARC)
• Webhooks processing bounces
• Seed tests to Gmail, Outlook, Yahoo personal inboxes

Sample warmup schedule (marketing list 10k+)

Day	Max recipients	Notes
1	200–500	Most engaged segment
2	500–1,000	Monitor bounces
3	1,000–2,000	Pause if complaint > 0.1%
4–7	Double every 2 days if clean
Week 2+	Approach full list	Split remaining by engagement

Adjust down if soft bounces or deferrals spike.

Segmentation tips

1. Most engaged first — opened/clicked in last 90 days.
2. Exclude never engaged until week 2.
3. Never import purchased lists to “speed up” warmup.

Transactional vs marketing

Transactional (receipts, password resets) can often send sooner on separate subdomain — still verify DNS and keep volume proportional.

Provider limits

• SES: request limit increases if throttling at account level.
• SendGrid/Mailgun: plan caps may require upgrade before full list.

Signals to pause

• Bounce rate > 5%
• Complaint rate > 0.1%
• Sudden spam folder placement on seeds

Fix list hygiene before continuing — see Bounce handling.