> For the complete documentation index, see [llms.txt](https://docs.cekat.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cekat.ai/en/ai-and-platform/chat/chat-box/chat-expiration-rules.md).

# Chat Expiration Rules

### WhatsApp chats and the 24-hour window

<figure><img src="https://3693109682-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZNZlvyOVkZXyd3pz2Cql%2Fuploads%2FBccrfeGkZyV4haWj1BV8%2FScreenshot%202025-05-23%20at%2011.01.33%E2%80%AFAM.png?alt=media&#x26;token=8029d7d7-1c58-4ce5-8aa0-902dbbaec5fa" alt="" width="375"><figcaption></figcaption></figure>

By default, WhatsApp only lets you reply with regular text within **24 hours** of the customer's last message. After that, you'll need to use a **template message** to reply.\
You can create templates ahead of time on the **Broadcast** page. [See how](https://docs.cekat.ai/en/chat/broadcasts)

**For example:** if a customer last messaged at 10:00, you can reply freely until 10:00 the next day.

<figure><img src="https://3693109682-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZNZlvyOVkZXyd3pz2Cql%2Fuploads%2FdUQuIJsa2nBVHwhpozXq%2FScreenshot%202025-05-23%20at%2011.02.03%E2%80%AFAM.png?alt=media&#x26;token=6c274050-ea13-4607-9fdf-435f54eb5984" alt="" width="375"><figcaption></figcaption></figure>

#### **Click to WhatsApp Ads (CTWA)**

If the conversation came from a **Click to WhatsApp Ad (CTWA)**, the conversation window still stays open for **24 hours**. However, you can send template messages free of charge for up to **72 hours** after the customer clicks the ad.