IP warming
Warming is the practice of raising volume on a new sending address slowly rather than all at once. Receiving servers judge an address they have never seen by how it behaves, and a sudden burst from an unknown one looks like a spam run. A warm-up sends a little on the first day and more each day after, watching bounces and complaints as it climbs.
At a glance
- Category
- Infrastructure
- Applies to
- A new dedicated address, or a domain with no history
- Shape
- A daily ramp, increasing while the signals stay clean
- Watched during
- Bounce rate, complaint rate, deferrals per provider
- Typical length
- Two to six weeks, depending on target volume
How it works
A ramp assigns a daily ceiling that grows over time, often roughly doubling while the signals stay healthy. The most engaged recipients go first, because their opens and replies are the evidence receiving servers use to form a favourable view. Bounces, complaints and deferrals are watched per provider at each step; if any rises, the ramp pauses or falls back rather than continuing. Traffic above the ceiling continues to go out over an already-warm path until the ramp is complete.
Why it matters
Receiving servers treat volume from an unknown source as the defining characteristic of a spam run, because it usually is. Sending your full load on day one from a cold address is therefore the fastest way to be filtered, and the reputation you earn in that first week is the one you then have to dig out of. A warm-up is slower but monotonic: each day of clean traffic makes the next day's volume easier to accept.
Example
A company moving to a dedicated address starts by sending its daily transactional mail to customers who opened something in the past month, a few thousand messages on the first day. The volume roughly doubles each day while bounces stay flat. On the second week one provider begins deferring, so the ramp holds at that level for three days until the deferrals stop, then resumes. After a month the full load is on the new address.
Common mistakes
- 01Starting a warm-up with the least engaged part of the list, which teaches every provider the wrong thing first.
- 02Continuing the ramp through rising complaints, which converts a pause into a reputation you will spend months repairing.
- 03Warming an address and then leaving it idle for weeks, so the reputation you built decays before you use it.
- 04Warming the address while the list itself is unclean, which builds a reputation on exactly the traffic you did not want measured.
In Rasket
A dedicated IP is warmed for you, and the plan settings show how far through the ramp it has got. Pricing
Related terms
Frequently asked questions
Do I need to warm a shared pool?
No. A shared pool is already warm because other senders keep traffic flowing through it, which is the main reason it suits low and irregular volume.
Does a domain need warming as well as an address?
Yes, in effect. Reputation is tracked against the sending domain as well as the address, so a brand-new domain benefits from the same gradual ramp even on a warm pool.
What if I have to send a large campaign mid-warm-up?
Send it over the warm path rather than the new address. Forcing a spike through a partially warmed address is the situation warming exists to avoid.
Last updated 16 September 2026.
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