How to start warm-up, and how long before you can send

Warm up a mailbox so its mail reaches the inbox, and see when it is ready

Updated 10 October 2026

Warm-up sends a small number of emails from your mailbox each day to other inboxes, which open them, reply to some and move them out of spam. This builds the mailbox's reputation, so Gmail and Outlook put its mail in the inbox. When you connect a new mailbox, SpamCipher usually starts warm-up for you. This guide shows how to check it is on, start it when it is not, and see when the mailbox is ready.

Note: How long it takes: warm-up starts at 3 emails a day and grows by about 30% a day, up to 40 a day, or the mailbox's daily limit if that is lower. It reaches 40 on its 11th warm-up day, and the mailbox counts as warmed after 14 warm-up days. Warm-up runs Monday to Friday unless you change it, so that is about three weeks.

Note: You can send before then. While a mailbox warms up, campaigns can already use it, but its daily limit starts at 5 and rises to the full limit over those 14 days, and warm-up emails count toward the same limit. So in the first two weeks only a few campaign emails, sometimes none, go out from it each day.

Note: Once warmed, warm-up keeps sending a smaller number each day to hold the reputation. These emails still count toward the mailbox's daily limit.

Note: If you pause warm-up on a mailbox, campaigns stop sending from it too, until you resume warm-up.

Before you start

A mailbox connected on Email Accounts
Ideally, your domain's SPF, DKIM and DMARC records already set up, if the mailbox uses your own domain
About 5 minutes

Start warm-up on a mailbox

Step 1: Open Email Accounts

In the left menu, point to the paper plane icon to open Outreach.
Click Email Accounts.

Step 2: Open the mailbox's warm-up settings

Find the mailbox you want to warm up.
Click Warm-up at the bottom of its card. A panel opens on the right.

Step 3: Enrol the mailbox

Check that Warm-up is on for this workspace is ticked. It applies to every mailbox.
If the panel says the mailbox is not in warm-up yet, click Enrol this mailbox in warm-up.
Warm-up starts today on your workspace's warm-up settings. You can change them for this mailbox in the same panel afterwards.

Note: If the panel shows warm-up settings instead of the Enrol button, the mailbox is already warming up. There is nothing more to start.

See when the mailbox is ready

Step 4: Open Warm-up

In the left menu, point to the inbox icon to open Inbox Management.
Click Warm-up.

Step 5: Open the mailbox

Your mailbox is in the list with its status, for example Warming.
Click Details on its row.

Step 6: Check its warm-up plan

Click Warm-up plan on the left.
Under Projected ramp, Starts at is how many warm-up emails it sends on the first day, Warm-up ceiling is the most it sends in a day, and Full pace by is the date it gets there.
The mailbox counts as warmed a few days after that, after 14 warm-up days in total.

Troubleshooting

My campaign is not sending from a mailbox that is warming up

Check the mailbox's card on Email Accounts. If it says warm-up is paused, click Resume warm-up. If warm-up is running, the mailbox may have used its daily limit, which is small early in warm-up and includes warm-up emails.

The card says warm-up isn't running

The card says why, for example that the mailbox can no longer sign in. Fix that, often by reconnecting the mailbox, then click Warm-up on the card and click I fixed it, resume warm-up.

Warm-up says Over your plan limit

Free workspaces warm up one mailbox, buying a credit pack raises that to five, and ONE warms up every mailbox. Click Add a warm-up mailbox to see your options.

Why does it only send 3 emails on the first day?

Warm-up starts small on purpose and grows each day. A sudden jump in sending from a new mailbox is what makes Gmail and Outlook send its mail to spam.

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