# Email Warmup

> Email warmup gradually ramps sending from a new inbox or domain to build sender reputation, so cold and marketing emails land in the inbox, not spam.

*Canonical: https://derrick-app.com/glossary/email-warmup*

---

**Email warmup is the process of gradually increasing the volume of messages sent from a new email address or domain, so mailbox providers learn to trust it.** A warmed inbox builds sender reputation over a few weeks, which helps cold and marketing emails land in the inbox instead of the spam folder.

New domains and inboxes start with no sending history, so providers like Gmail and Outlook treat sudden high volume as suspicious. Warmup avoids that by starting with a handful of emails per day and ramping up steadily, ideally with real replies and engagement mixed in. Over two to four weeks the sender earns a positive reputation. Warmup is about the sending side of email; it is separate from finding and verifying recipient addresses, though the two connect: sending to invalid addresses creates bounces that damage the reputation warmup is meant to build, so clean, verified lists protect the work.

## Example

A team registers a new sending domain for cold outreach. Week one they send 5 to 10 emails a day to engaged contacts; week two, 20 a day; week three, 40, with replies sprinkled in. By week four the domain has a track record, and only then do they launch the main campaign. Skipping this would have parked most messages in spam.

## Related definitions

- [Email Deliverability](https://derrick-app.com/glossary/email-deliverability)
- [Cold Email](https://derrick-app.com/glossary/cold-email)
- [Bounce Rate](https://derrick-app.com/glossary/bounce-rate)
- [Open Rate](https://derrick-app.com/glossary/open-rate)