> ## Documentation Index
> Fetch the complete documentation index at: https://help.lobyco.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Warm up email sending
> Split customers who agreed to email into one audience per day, then send each audience its own email.
When you start sending from a new domain, mailbox providers watch how many emails you send. This page shows you how to send to a few customers on the first day and a few more each day after. You split your customers into one audience per day on the canvas, then give each audience its own email. Why this matters is on [Deliverability](/business-documentation/communication/email/deliverability).
## What you'll build
```mermaid theme={"system"}
flowchart TB
A["Member segment
with email consent"] --> B[Split]
B --> C["Day 1
group"] --> F["Channel to the
Day 1 audience"]
B --> D["Day 2
group"] --> G["Channel to the
Day 2 audience"]
B --> E["More
days"]
F -.-> H["Email
on day 1"]
G -.-> I["Email
on day 2"]
```
There's one **Channel** block for each day. Each one puts the customers who reach it into that day's audience. A **Channel** block doesn't send them anything, so it isn't one of the [communications](/business-documentation/communication) such as push or email. Each email then sends to one of those audiences, on its own day.
## Settings
| Setting | What to set here |
| - | - |
| **Member segment** | A consent attribute from **Consent**, so only customers who agreed to email are included. |
| **Split** | **Build random split**, sized by **Target number**, with one group per day. It picks each day's customers at random. |
| **Channel**, one per group | **Location** set to **Audience**, with a new audience for that day. Its **Destination(s)** include **Email**, or are set with **Select all**. |
| **Email**, one per day | **Audience** on **Segmentation**, with that day's audience picked. Its **Start date** is the day it goes out. |
If the campaign has dates, the emails' dates have to fall inside them. So make sure the campaign runs for the whole warm-up, 14 days for example.
## Find customers who agreed to email
Open the campaign's **Orchestration** view. Add a **Member segment** from the **Block library** and open it. In **Create member segment**, choose **From Scratch**.
On **Segment attributes**, open **Consent** and add the attribute for email consent. If it asks for a **Name**, pick your email consent there. Leave **Version** empty to include every version.
Add any other attributes you need. The Split picks each day's customers at random, so it can't put your most engaged customers first. To warm up with engaged customers only, add attributes here that pick them. Leave the others out until the warm-up is over.
## Split them into daily groups
Add a **Split** and connect the **Member segment** to it. Then open the Split and select **Build random split**.
On the next step, give the Split a **Name**. Leave the size column on **Target number**. Then add one group per day with **Add split group**. Name each group after its day, and set its size to that day's number of emails. For example, 500 for day 1 and 650 for day 2. The [warm-up schedule](/business-documentation/communication/email/deliverability#warm-up-a-new-sending-domain) has a full 14-day example.
Every split also gets a last group called **Other**. It holds the customers who didn't fit in any day. Don't connect it to anything.
Select **Add attribute split** to save the groups. [Split a segment into groups](/business-documentation/use-cases/split-a-segment-into-groups) shows the Split block step by step, and the [Block reference](/business-documentation/campaigns/orchestration-canvas/block-reference#split) lists every setting.
## Send each group to its own audience
Add a **Channel** for each day's group, and connect the group to it.
Open each Channel. Give it a **Name**, and set **Location** to **Audience**. Then select **Create new audience** and name it after the day, such as *Warm-up day 1*. Under **Destination(s)**, choose **Email**. If **Email** isn't in the list, choose **Select all**. Either one lets an email use the audience. Then select **Create**.
*The split flow, with one Channel per day*
## Run the flow once
Save the canvas, then run the flow once with **Execute**. See [Or run it now](/business-documentation/campaigns/schedule-and-run-a-campaign#or-run-it-now).
> [!WARNING]
>
> Each run replaces the customers in these audiences. Run the flow once, and don't schedule more runs. Otherwise, a day's audience can change before its email goes out.
## Create one email per day
Go to the campaign's **List** view and select **Add activity**. On the **Email** tile, select **From scratch**. An email you add from the **List** view isn't connected to any block, so it sends to an audience.
Fill in the email as described in [Emails](/business-documentation/communication/email). Two settings make it part of the warm-up.
* On **Activity details**, set **Start date** to the day and time this email goes out. An email that sends to an audience goes out once, at its start date. Each email starts one day after the one before.
* On **Segmentation**, **Audience** is already chosen, because an email can't go to every customer. Under **Select Audience**, choose **Select from list** and pick that day's audience.
To save time, save the first email, then choose **Save as template** from the arrow beside **Save**. Start the other emails with **From template**, then change the dates and the audience.
## Publish each email
Select **Publish** on each email and confirm. Because the start date is in the future, the portal says the email *will automatically become active on* that date.
## Check the result
Two checks tell you the warm-up is set up.
* Open any email's **Segmentation** and choose **Select from list**. The **Size** column shows how many customers each day's audience holds. It should match your plan.
* In the campaign's **List** view, each email shows **Scheduled** until its day, then **Active**.
To see how the emails performed, go to [Measure](/business-documentation/measure).
## Variation: split a file instead
If you already have the list as a file, you can skip the canvas.
1. Start from a CSV file of member IDs, one per line. This upload isn't the same as a **[Seed](/business-documentation/use-cases/use-an-imported-customer-list-instead-of-a-segment)** block's, so the file can have a header row with a `MemberId` or `CustomerId` column.
2. Split it into one file per day, with that day's number of customers in each.
3. Create one email per day as described above. On **Segmentation**, choose **Create new audience** instead of **Select from list**. Name the audience, upload that day's file and select **Create**.
## Related
* [Deliverability](/business-documentation/communication/email/deliverability) explains why to warm up, and what to do if the warm-up is interrupted.
* [Emails](/business-documentation/communication/email) covers every field on the email form.
* [Split a segment into groups](/business-documentation/use-cases/split-a-segment-into-groups) shows the Split block on its own.
* [Block reference](/business-documentation/campaigns/orchestration-canvas/block-reference) describes the Split and Channel blocks in full.
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