Glossary
Domain warming
Also called IP warming, warm-up.
Last reviewed 18 September 2026
How long does it take to warm up a sending domain?
Domain warming is the practice of raising the volume sent from a new domain gradually, over something like two to four weeks, so that a domain with no reputation does not arrive looking like one registered this morning for a campaign.
Neither Google nor Yahoo publishes a ramp; both say only to increase volume gradually and watch the signals, so anyone quoting a schedule to three decimal places is quoting a habit. The shape most senders use is a few hundred messages a day to the addresses most likely to engage, held for two or three days, then roughly doubling every two to three days while complaint and soft bounce rates stay flat.
If a rate moves you hold rather than push through. A course sender gets part of this for free, because a course fans out one message per subscriber per day rather than one blast to everybody at once.
See also
- Sending domain
A sending domain is the domain that signs and sends your mail, and it is worth separating from the sending infrastructure: the IP addresses mail leaves from are shared by default at every provider serving small senders, while the domain in the signature and the From line is yours alone.
- Sender reputation
Sender reputation is what a mailbox provider has learned about the domain and the infrastructure your mail comes from, assembled from complaints, bounces, spam trap hits and how the people who receive your mail behave, and it is what decides the folder.
- Throttling
Throttling is a receiving provider deliberately slowing or temporarily refusing mail from a sender, usually with a 4xx response, because the volume, the pattern or the reputation it is seeing is more than it is willing to accept right now.
Read next
This term is covered properly in Email deliverability for small senders: authentication and reputation, which is a longer piece on the subject.
Every other term is on the glossary index , the longer writing is in the guides, and what this site itself does is on the home page.
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