The WhatsApp 24-hour window is the period after a customer’s last message during which a business on the API can reply freely. Once 24 hours pass without a new customer message, you can only reach them with an approved template. Understanding this one rule explains most “why can’t I reply?” moments. It is one part of our guide to the WhatsApp Business API in the UAE.
What opens the window
Meta calls it the customer service window. According to Meta’s WhatsApp pricing documentation, a 24-hour window opens when a customer contacts you.
Examples that open or refresh it:
- A customer sends “Hi, is this available?” from your website button.
- A customer replies to your order update with “Thanks”.
- A customer sends a photo or location in an existing chat.
Your own messages do not open the window. Only the customer’s messages do.
What you can send inside it
While the window is open, your team or AI assistant can reply with normal messages: text, photos, documents, links and locations. Meta’s page states that “Non-template messages can only be sent within an open customer service window”, and that “All non-template messages are free”.
A simple timeline:
| Time | What happens |
|---|---|
| 09:00 Monday | Customer asks about a delivery slot. Window opens until 09:00 Tuesday. |
| 11:30 Monday | You reply with options. The window end does not move. |
| 18:00 Monday | Customer replies “Tuesday afternoon please”. Window now runs to 18:00 Tuesday. |
| After 18:00 Tuesday | No new customer message. Window closed. |
Two practical tips follow from this. First, answer new enquiries as soon as you can, ideally while the customer is still online. Second, if you need information from the customer, ask for everything in one message, so their reply keeps the window open while you prepare a quote or an order.
What happens after 24 hours
Once the window closes, normal messages are blocked. You will see an error or your provider will stop you sending. This is not a fault on your number. It is Meta’s design, intended to stop businesses messaging people who have gone quiet.
Teams often meet this rule when a customer asks for a quote on Thursday and the reply is only ready on Saturday. By then, a normal message will not go through. Planning around the window avoids that frustration.
At this point you have two options: wait for the customer to write again, or send an approved template.
Re-opening a conversation with a template
A template is a pre-approved message, and Meta may charge for it depending on its category. If the customer replies to your template, a new window opens and you can talk normally again. Our help article on setting up message templates covers the steps.
A useful re-opening template is short and gives a clear reason to reply:
Hello {{1}}, you asked us about {{2}} earlier this week. Would you like us to hold one for you? Just reply here.
Keep re-opening messages relevant to what the customer asked. Sending unrelated offers to restart chats can lead to blocks and reports.
Planning follow-ups around the window
Good follow-up timing uses the window rather than fighting it. A reminder sent while the window is open is an ordinary message. One sent after it has closed needs a template.
- Early follow-ups (a few hours after the enquiry) usually fall inside the window.
- Next-day follow-ups often land near the edge, so plan a template version.
- Later follow-ups almost always need a template.
We explain a practical rhythm in our article on WhatsApp follow-up timing at 2h, 24h and 48h.
Write each follow-up in two forms: a normal message for when the window is still open, and an approved template for when it has closed. That way, the timing can change without the message failing to send.
How Dub Ai helps
Dub Ai’s business-specific AI assistant answers incoming chats from your own information as they arrive, so most questions are handled while the window is open. When a customer goes quiet, follow-ups run on a schedule, with 2-hour, 24-hour and 48-hour steps as defaults you can change. Our help centre’s overview of follow-ups explains how each step uses a normal message or an approved template depending on the window. The Dub Ai team writes and submits those templates for you.
Frequently asked questions
Does the window reset when the customer replies?
Yes. Each new message from the customer starts a fresh 24-hour window from that moment. Your own replies do not extend it. If a customer answers your template the next morning, you can continue the conversation normally for another 24 hours from their reply, without needing another template.
Can I send a photo after 24 hours?
Not as a normal message. Once the window has closed, everything you send must be an approved template. A template can include a header image or document if it was approved that way. Otherwise, send a short template asking whether the customer would like the photo, and share it once they reply.
Book your demo on WhatsApp: +971 56 552 6662
Sources
- WhatsApp Business Platform: Pricing (Meta for Developers, checked October 2026)