> For the complete documentation index, see [llms.txt](https://docs.channel360.co.za/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.channel360.co.za/api-usage/concepts/notifications-vs-replies.md).

# Notifications vs. replies (the 24-hour window)

When to send a template notification and when you can reply freely — the 24-hour window.

You can message anyone who agreed to hear from you with a template. You can only send free-form replies within 24 hours of the customer's latest message.

## The two ways to send

|                      | Template notification                                                      | Reply                                                     |
| -------------------- | -------------------------------------------------------------------------- | --------------------------------------------------------- |
| What it is           | An approved template                                                       | Free-form: text, media, buttons, lists, Flows             |
| When you can send it | Any time, to anyone who agreed to hear from you                            | Only within 24 hours of the customer's latest message     |
| Who you address      | A phone number (`destination`)                                             | An app user ID (`<APP_USER_ID>`)                          |
| Endpoint             | `POST /org/<ORG_ID>/notification`                                          | `POST /org/<ORG_ID>/whatsapp/appuser/<APP_USER_ID>/reply` |
| Delivery events      | `notification:delivery:channel` / `:user` / `:failure`                     | `message:delivery:channel` / `:user` / `:failure`         |
| Guide                | [Send a template notification](/api-usage/send-a-template-notification.md) | [Reply to a customer](/api-usage/reply-to-a-customer.md)  |

## How the window works

The window opens, or restarts, every time the customer sends you a message. For the next 24 hours you can reply with anything.

When the window has closed, send a template notification. If the customer answers it, the window opens again and you can reply freely.

## Related

{% content-ref url="/pages/g7KUSUMWQLS6klQCKU15" %}
[Identifiers: which ID is which](/api-usage/concepts/identifiers.md)
{% endcontent-ref %}