> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cliqo.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Warm-up: how to send to a new list

> Why you shouldn't blast everyone at once — and the practical plan of slices, measurement and pacing.

## What you will learn

How to build sending reputation with a list that has never received your email (or hasn't in a long time) — slicing, measuring and growing with each send.

## Why warm up

Mailbox providers judge senders by recent behavior: sudden volume from a new sender, with bounces and complaints together, is exactly the signature of spam. Thousands of cold emails at once is the biggest reputational risk a new account can take — and a burned reputation takes weeks to recover. Warming up trades one big risk for several small, measurable ones.

## The slice plan

1. **Start with your most engaged people.** First slice of about a thousand contacts — the ones who bought or opened something recently. If your list came from another tool, use its history to choose.
2. **Measure before you grow.** After the send, open the **Delivery of sent** section of the campaign report: **hard bounces below 2%** and **complaints below 0.1%** are the limits — above them, the row is tagged **above threshold**. Within them, double the slice on the next send; outside them, stop and investigate before continuing — the problem is usually list quality, not content.
3. **Repeat until you cover the list.** Doubling after each healthy send reaches your entire list in a few weeks, with your reputation built along the way.

## Use send pacing

Even within a slice, spread it out: when setting up the campaign, in the **Delivery** step, **Send pacing** distributes the send over 1, 4, 8 or 24 hours instead of releasing everything in the same minute (**Instant**). For large lists, this avoids the spikes that trigger blocking at the providers. Pacing is self-correcting — the campaign finishes at the scheduled time.

## What to watch on each send

* **Bounces** — above 2%, the list has dead addresses: clean it before growing.
* **Complaints (spam)** — above 0.1% is a red flag: review consent and frequency, not just the subject line.
* **Unsubscribes** — healthy is below 1%; a spike means the wrong audience for the message.
* **Needs attention** — the bell warns you automatically when the bounce rate goes above 2% or the complaint rate goes above 0.1%, measured over the sends of the last 30 days (from 20 sends up). Unsubscribes don't show in the bell: track them in the campaign report.

## What about WhatsApp?

WhatsApp has its own version of this: sends **in waves**, with the number's daily limit and automatic safeguards that pause the campaign if blocks rise or the number's quality rating drops. It's covered in [How to send a bulk message](https://docs.cliqo.io/en/whatsapp/enviar-em-massa.md).

## Related articles

* [Checklist before your first send](https://docs.cliqo.io/en/entregabilidade/checklist-primeiro-envio.md)
* [Understand Cliqo's metrics](https://docs.cliqo.io/en/relatorios/entenda-metricas.md)


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