The WhatsApp 24 hour window, in plain English (October 2026)

A customer messages your shop at 10:00 on Monday asking if a jacket comes in blue. Your team gets busy. At 11:30 on Tuesday someone finally types a reply, and the message box won't let them send it.

Nothing is broken. That is the WhatsApp 24 hour window doing exactly what it was built to do, and once you understand it, it stops being annoying. This guide covers what opens it, what you can send inside and outside it, and the pricing changes Meta made on 1 October 2026. Details are as of October 2026 and Meta does change them, so use the links to check.

What opens the WhatsApp 24 hour window, and what doesn't

Meta calls it the customer service window. In its words, when a WhatsApp user messages you or calls you, a 24-hour timer starts. If they message or call again before it runs out, the timer resets to 24 hours.

Two things follow from that.

First, only the customer can open or extend it. Your replies don't add time. A long back-and-forth stays open because the customer keeps writing, not because you do.

Second, sending a template doesn't open it either. When a template brings someone back and they answer, a new window opens then.

If you use the WhatsApp Business app alongside a platform (Coexistence), Meta's onboarding documentation says messages sent from the app are not subject to the window and don't create or extend it. It also says a window opens only when a customer messages you, so someone who wrote before your number was connected hasn't opened one. Until they write again, you're limited to templates for that person.

What you can send inside the window

While the window is open you can send what Meta calls service messages: text, images, video, audio, documents, stickers, locations and contacts, plus interactive messages such as reply buttons, lists, link buttons and Flows. No pre-approval needed.

What you can send outside it

Only an approved template. That is the whole rule. Templates can be sent at any time, with no window needed, but they have to be reviewed first, and they're priced by category. If you haven't written one yet, our guide to getting WhatsApp message templates approved is the place to start.

A good habit: end a template with a question or a quick-reply button. If the customer taps it, a fresh window opens and you can carry on in free-form.

The October 2026 changes

This is the part that changed. According to Meta's pricing documentation, two things took effect on 1 October 2026:

• Service messages beyond a free tier became chargeable. Each business phone number gets 1,000 free delivered service messages per month. Meta charges from the 1,001st. The allowance resets each month and doesn't roll over. Service messages had been free since November 2024.
• Utility templates sent inside an open window became chargeable too. They had been free since July 2025. Meta's status webhooks now show these as regular instead of free_customer_service.

Some other points from the same page:

• Messages from customers to you are free.
• If you have no payment method on your account, service messages inside the free tier are still delivered, but not those beyond it. Meta said it would stop delivering service messages once they became chargeable.
• Eligible governments and non-profits keep service messages free beyond the monthly tier, under a separate policy.
• A customer who messages you from a Click-to-WhatsApp ad opens a free entry point window. Meta's page says messages in it are free and the window may stay open for up to 7 days. Older Meta pages mention 72 hours, so check the current wording.

We are deliberately not quoting what each message costs. Rates depend on the message type and the customer's country, and they're published on Meta's rate card. Our overview of WhatsApp Business API pricing shows how to put the pieces together.

Working with the 24 hour window, day to day

• Reply while it's open. In the Avox Inbox, the chat header shows the time left, for example "Reply window: 5h 12m left". It turns amber under two hours and reads "Reply window closed" afterwards. See the messaging window guide.
• Let an automation catch the quiet hours. Avox automations send inside the window; the Send a template action is the one message action that still works after it closes. Every other message step is skipped when the window has shut, and the automation moves on.
• Keep a few utility templates ready, one for each common reason you'd need to get back in touch: a booking reminder, an order update, a payment reminder. The template library is a quick way to start.
• Mind the API. If you send a free-form message outside the window through the Avox API, you get an outside_messaging_window error, which corresponds to Meta's error 131047. Send a template instead.
• The window belongs to one number. A customer who wrote to your sales line hasn't opened a window on your support line.

Wondering how your business app fits in? See our Coexistence guide.

Questions people ask

Does a phone call open the window?

Yes. Meta's pricing page says that when a user messages or calls you, the 24-hour timer starts, and a new message or call resets it.

If I reply, does that give me another 24 hours?

No. Only the customer's messages or calls restart the timer. Your reply doesn't extend it.

Can I message someone who never wrote to me?

Only with an approved template, and you should have their permission first. We cover how to get and record it in our guide to WhatsApp opt-in.

Are the 1,000 free service messages per month for my whole account?

Meta's page says each business phone number has one free tier of 1,000 delivered service messages a month. If you have several numbers, each has its own tier. Check the page, as terms can change.

Your next step: open your busiest week of conversations, count how many replies went out as service messages, and see how close you come to 1,000 per number.