---
title: "Customer service window"
description: "Learn how the 24-hour customer service window works and the difference between session and template messages."
---

> Documentation Index
> Fetch the complete documentation index at: https://docs.wazapin.id/llms.txt
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# Customer service window

WhatsApp enforces a **24-hour customer service window** to prevent spam and encourage quick support replies. The type of message you can send depends on whether this window is currently open or closed.

## When this matters

Understanding the customer service window is crucial when:
- Designing automated chatbots or interactive support flows.
- Sending transactional alerts, OTPs, or marketing notifications.
- Handling agent-led customer service conversations.

## Key rules

| Message Type | Session (Free-form) | Template |
| :--- | :--- | :--- |
| **Trigger** | Opened when a user sends an inbound message to your number. | Sent at any time, including when the window is closed. |
| **Duration** | Valid for 24 hours from the last user message. | No expiration. |
| **Content** | Any supported format (text, media, buttons, lists) with free-form text. | Pre-approved templates only. Must use defined variables. |
| **Cost** | Typically billed as user-initiated conversations. | Typically billed as business-initiated conversations. |

## How the window works

When a customer sends a message to your WhatsApp Business number, it opens the customer service window. 

1. **Active Session (Within 24 Hours):** Your business can send free-form messages (session messages) to the user. Each time the user replies, the 24-hour timer resets.
2. **Expired Session (After 24 Hours):** Once 24 hours have passed since the user's last message, the window closes. You can no longer send free-form messages. To resume messaging, you must send an approved template message.

:::note
On unofficial channels, the 24-hour customer service window is not technically enforced by Meta, but adhering to it is highly recommended to protect your number from being blocked for spam.
:::

## Related links
- [Send templates](/getting-started/send-template)
- [Message lifecycle](/whatsapp-basics/message-lifecycle)
- [Channel support matrix](/api/channel-support)

Source: https://docs.wazapin.id/whatsapp-basics/session-window/index.mdx