# Email warm-up

> The gradual ramp that teaches mailbox providers to trust a new sender — ramp curves, engagement simulation, and the maintenance floor that follows.

**Warm-up gradually increases sending volume on a new mailbox or domain so providers learn to trust it. Typical ramps start at 5-10 emails per day and grow 10-20% daily over 3-8 weeks. Warm-up tools also simulate engagement between peer inboxes. A maintenance floor keeps the reputation alive after ramp-up.**

_Status: Reviewed — human-edited, facts not yet confirmed against the product._

## What it is

Warm-up is the controlled ramp of sending activity on a new mailbox or domain, designed
to build [sender reputation](/learn/sender-reputation) before real outreach begins. It
has two parts: a gradual volume increase, and simulated engagement — warm-up tools
exchange messages across a network of peer inboxes that open, reply, and rescue mail
from spam.

## Why it works this way

Providers have no history for a new identity, so they assume the worst. A fresh mailbox
that immediately sends hundreds of emails looks exactly like a compromised account —
sudden volume is the primary signature of abuse. Providers therefore throttle or
spam-folder unknown senders until weeks of consistent, engaged-with sending prove the
identity is legitimate. Warm-up manufactures that history deliberately.

## How it behaves in practice

- **Typical ramp curve.** Start around 5-10 emails per day, increase roughly 10-20% per day, and reach target volume in about 3-8 weeks depending on goal and domain age.
- **Engagement is simulated first.** Peer-network replies and spam rescues supply positive signals before real prospects exist to provide them.
- **"Done" is a state, not a date.** Warm-up is finished when volume is at target, placement is stable, and engagement holds — not after a fixed number of days.
- **Keep a maintenance floor.** A mailbox that stops warm-up entirely cools down; most programs keep a low background level running alongside real sending.
- **Domain and mailbox warm separately.** A warmed domain shortens, but does not remove, the ramp for a new mailbox on it.

## Common misconceptions

| Belief | Reality |
| --- | --- |
| "Warm-up is a one-time setup" | Reputation decays; paused or seasonal mailboxes cool and need re-warming |
| "Warm-up tools guarantee inbox placement" | They build history; list quality, targeting, and content still decide placement |
| "A good domain lets you skip warm-up" | Reputation is also scoped per mailbox — a new mailbox still starts near zero |
| "A faster ramp gets results sooner" | Volume spikes read as compromise and can reset the trust already built |

## How Reply implements this

Reply splits the ramp into two features as part of its
[deliverability capability](/capabilities/deliverability). **Warm-up** runs through
MailToaster — included with paid subscriptions, with one warm-up seat per mailbox
connected in Reply — which builds reputation by simulating natural email exchanges
across a peer network. You pick a warm-up profile (**New email account**,
**Reputation protect**, or a custom one) and set a daily goal with a daily increment.
**Ramp-up** runs inside Reply and is active by default for every newly added email
account: the default curve starts at 10 emails per day and adds 3 daily until it
reaches 100. Reply's recommended order is warm up first, then ramp up real sending —
and keep warm-up enabled for as long as you send cold email, which is the maintenance
floor described above. Per-mailbox [sending limits](/how-to/configure-sending-limits)
hold real outreach inside the ramp after you
[connect a mailbox](/how-to/connect-a-mailbox).

## Where this breaks down

Warm-up builds trust; it cannot repair a burned domain on any useful timescale. Simulated
engagement is also not real engagement — providers reportedly discount traffic they can
identify as warm-up networks. Once real sending starts, placement depends on your list
and content, and no ramp compensates for either.

## Related

- [Email deliverability](/learn/email-deliverability)
- [Sender reputation](/learn/sender-reputation)
- [SPF, DKIM, DMARC](/learn/spf-dkim-dmarc)
- [Deliverability in Reply](/capabilities/deliverability)

## Build with Reply

- REST API: [docs.reply.io](https://docs.reply.io/api-reference/introduction) — email account setup and limits
- MCP: [agents.reply.io/mcp](https://agents.reply.io/mcp) — warm-up connect and status operations