> ## Documentation Index > Fetch the complete documentation index at: https://help.chatarmin.com/llms.txt > Use this file to discover all available pages before exploring further. # What is the 24-Hour Window? > Chatarmin guide: What is the 24-Hour Window? The **24-hour window** is a core part of how **WhatsApp with Chatarmin** messaging works. It’s designed to promote fast, customer-friendly conversations between businesses and users - while preventing spam and unwanted messages. *** ## 🕐 **How the 24-Hour Window Works** *** When a **customer sends a message** to your business (for example, by asking a question, replying to a campaign, or requesting support), WhatsApp automatically opens a **24-hour service window**. During this 24-hour period: * Your business can reply to the customer **as often as needed** * You can send **free-form messages** (any text, media, buttons, etc.) This window gives your team the flexibility to **resolve issues, follow up, or continue conversations naturally**, without any restrictions or additional fees. Chatarmin help center image *** ## ❓What Happens After 24 Hours? *** If the customer does **not send another message** within 24 hours, the window **closes**. At that point: * You can **no longer send free replies** * WhatsApp blocks free-form messages * The only way to re-engage is by sending a **paid, pre-approved message template** As soon as the customer sends **any new message**, a **new 24-hour window opens**. Template messages outside the 24h window must be **approved by Meta** in advance and may have different pricing depending on their type (Marketing, Utility, Authentication). **Want to understand how Meta charges for messages?**\ 👉 [Here is an article explaining how Meta’s pricing works](/billing/meta-pricing)