The 24-hour window is the line that separates what you can send freely from what requires a template. Most of the pricing model follows from it.
Customer writes
A 24-hour window opens.
You reply free-form
A service message inside the window. Free through September 30, billed from October 1, 2026.
Customer writes again
Every customer message resets the window. A fresh 24 hours starts now.
The window closes
24 hours passed with no new customer message. Free-form messaging stops.
You send a template
The window is closed, so free-form is rejected. An approved template goes out instead, billed by category.
How it works
When a customer sends you a message, a 24-hour window opens. Inside it, you can reply with anything: free-form text, images, interactive messages, buttons, lists. No template, no approval, no pre-registration.
Every new inbound message from that customer resets the window to a fresh 24 hours. A conversation that runs over several days stays open the whole time, as long as the customer keeps replying.
When the window closes, free-form messaging stops. To reach that customer again you must send an approved template, which opens a new interaction and is billed under its own category.
What this means through September 30, 2026
As of now, the window is also a billing boundary:
- Inbound messages: always free, however many arrive.
- Free-form outbound inside the window: these are
servicemessages, and they are free. - Utility templates inside the window: these are also free through September 30.
- Outbound outside the window: requires a template, billed as
marketing,utilityorauthentication.
A twenty-message support conversation costs nothing through September 30, as long as the customer opened it. From October 1, the window still controls what you may send, but it no longer makes service messages or utility templates free.
A support reply vs an order notification
A support reply happens inside the window, because the customer opened the conversation by writing in. Free through September 30; billed from October 1.
An order notification is sent outside any window, because nothing the customer sent opened one. Billed, always.
The window isn't the same as a conversation
Older WhatsApp pricing documentation describes conversation-based billing, where you paid once to open a 24-hour conversation and everything you sent inside it was included. That model is gone; pricing is now per message.
The window still exists and still governs what you're allowed to send. It no longer bundles a set of messages into a single charge. If you find a blog post describing conversation-based pricing, it predates the current model, and its arithmetic won't match your invoice.