# IP warming: Definition and How It Works

Source: https://wraps.dev/glossary/ip-warming

DeliverabilityIP ramp-upwarming a sending IP

IP warming is the gradual, staged increase of sending volume on a new IP so mailbox providers can build a reputation baseline for it before it carries full-scale traffic.

## Why a cold IP gets filtered even with clean content

Mailbox providers weigh sending IP reputation heavily, and a brand-new IP has no history at all — no baseline of how recipients respond to mail from it. A sudden burst of high volume from an IP with zero sending history looks statistically identical to the start of a spam run, regardless of how legitimate the actual content is, which is why providers apply heavier filtering to unfamiliar IPs by default.

## What a warming schedule actually does

A warming plan starts at a small daily volume — often just a few hundred messages — sent to the most engaged, most likely-to-open portion of a list, and increases volume incrementally over roughly two to four weeks as positive engagement (opens, replies, low complaints) accumulates. The goal is giving mailbox providers a growing, positive signal to attach to the IP before it ever needs to carry peak volume.

## This mostly matters for dedicated IPs

A shared IP pool, like SES's default sending infrastructure, already carries an aggregate reputation built from every sender using it, so a new account sending through it doesn't start from zero the way a freshly provisioned dedicated IP does. Warming is primarily a dedicated-IP concern — it's the price of owning your own reputation rather than borrowing a pool's established one.

## Sending to your worst engagement segment first undoes it

Warming works because it front-loads positive signal onto an unproven IP. Sending a re-engagement campaign, a purchased list, or any low-engagement segment during the warming window does the opposite of what warming is for — it attaches the negative signal that's most damaging precisely to the IP that has the least existing reputation to absorb it.

## Why it matters

Skipping IP warming on a new dedicated IP is one of the most common ways a deliverability problem gets self-inflicted right at launch — the technical setup (SPF, DKIM, DMARC) can be perfect and the IP still gets aggressively filtered simply because mailbox providers have no reason yet to trust it at volume.

## Common questions

### How long does IP warming take?

Typically two to four weeks, starting at a low daily volume sent to the most engaged subscribers and increasing incrementally as positive engagement accumulates, rather than a fixed schedule that applies identically to every sender.

### Do I need to warm up SES's shared sending IPs?

No. Shared IP pools already carry an aggregate reputation built from every sender using them, so a new account doesn't start from zero the way a freshly provisioned dedicated IP does. Warming is a dedicated-IP concern.

### What happens if I send to a low-engagement list during IP warming?

It undermines the entire point. Warming works by attaching positive signal to an unproven IP first — sending to a stale or purchased list during that window attaches negative signal precisely when the IP has the least reputation built up to absorb it.