Glossary Deliverability
What is email warm-up for a new mailbox?
Email warm-up is the practice of starting a new or quiet mailbox at a small number of emails a day and raising it gradually, so mailbox providers build trust in the sender before volume grows.
A brand new mailbox that suddenly sends dozens of emails to strangers looks like a spammer to Gmail and Outlook. Raising volume over a couple of weeks gives providers a history of normal, wanted mail to judge you by.
Warm-up only works if the emails themselves are wanted: sent to real, checked addresses, personal enough to get replies and rarely marked as spam.
Why it matters
- Skipping warm-up is one of the fastest ways to land a new domain in spam.
- A slow start limits the damage if a list or message has a problem.
- Steady, low volume is also what one-to-one outreach looks like, which is the point.
How Reach Crew handles it
Reach Crew warms up every new mailbox on its own over about two weeks. A personal Gmail goes 5, 8, 12, then 20 first emails a day. A Google Workspace mailbox goes 5, 10, 20, then 30.
Related terms
- Sending limits. Sending limits are the maximum number of emails or recipients a mailbox provider lets one account send in a...
- Sender reputation. Sender reputation is the trust that mailbox providers such as Gmail and Outlook place in a sending domain or...
- Email deliverability. Email deliverability is the share of the emails you send that land in the recipient's inbox, rather than in...
- Bounce rate. Bounce rate is the percentage of sent emails that come back as undeliverable, usually because the address does...
- Guide: Email warm-up and sending limits for a new mailbox