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

# Messaging model

> The 24-hour Customer Service Window and what you can send when

WhatsApp is not SMS. What you can send to a user depends on **who
initiated the conversation** and **how long ago**. This page explains
the one rule that shapes everything else — the **24-hour Customer
Service Window**.

For category and pricing details, see:

<CardGroup cols={2}>
  <Card title="Template categories" href="/guides/whatsapp/template-categories">
    Marketing, Utility, Authentication, and when to use each.
  </Card>

  <Card title="Pricing" href="/guides/whatsapp/pricing">
    How Meta charges, the free-message scenarios, and volume tiers.
  </Card>
</CardGroup>

## The 24-hour Customer Service Window (CSW)

A **Customer Service Window** opens when the user sends you a message.
For the next 24 hours you can reply with any message type — free-form
text, media, interactive buttons, lists — without using a template.

Once 24 hours pass from the user's last inbound message, the window
closes. After that, the **only** thing you can send is a pre-approved
**template message**.

<Info>
  The window resets every time the user sends you a new inbound message.
  There is no way to extend it by sending outbound messages.
</Info>

### What opens or resets the window

* Any inbound message from the user (text, media, interactive reply,
  location, contacts, reaction)
* A tap on a Quick Reply button that emits a reply
* A **WhatsApp voice call from the user to your business**

### What does not open or reset the window

* A delivery or read receipt on a message you sent
* A template send from your side (you opened outbound, not inbound)
* An outbound call you placed to the user

### Where you see it

In the **Conversations** view, each thread shows the session clock and
whether the window is open or closed. When closed, the free-form
composer is disabled and only the template picker is available.

## What you can send when

| Scenario                                    | Free-form |    Template    |
| ------------------------------------------- | :-------: | :------------: |
| User replied in the last 24h (CSW open)     |     ✅     |        ✅       |
| User replied more than 24h ago (CSW closed) |     —     |        ✅       |
| User has never messaged you (cold outreach) |     —     | ✅ (per opt-in) |
| User opted out (globally or for this list)  |     —     |        —       |
| Template is approved                        |    n/a    |        ✅       |
| Template is pending / rejected / paused     |    n/a    |        —       |

What each scenario costs is a separate question — see
[Pricing](/guides/whatsapp/pricing) for the free scenarios and the
per-message charges.

<Warning>
  Sending Marketing templates to users who did not opt in violates
  Meta's WhatsApp Business policies and will degrade your number's
  quality score. See [Compliance](/guides/whatsapp/compliance).
</Warning>

## What's next

<CardGroup cols={2}>
  <Card title="Template categories" href="/guides/whatsapp/template-categories">
    Marketing, Utility, Authentication, reclassification, and CPR.
  </Card>

  <Card title="Pricing" href="/guides/whatsapp/pricing">
    How Meta charges and when messages are free.
  </Card>

  <Card title="Per-user marketing limits" href="/guides/whatsapp/per-user-marketing-limits">
    The dynamic cap Meta applies per user — one of the most common
    reasons marketing messages silently don't deliver.
  </Card>

  <Card title="Quality and limits" href="/guides/whatsapp/quality-and-limits">
    Number quality, messaging tiers, and the rate limits that apply to
    your sends.
  </Card>
</CardGroup>