24-hour window

The 24-hour window (customer service window) is the official WhatsApp API rule that sets when a business can reply with any text. It opens when the customer sends a message and lasts 24 hours from their last message; every new message from the customer restarts the count.

Inside and outside the window

Inside the window, the business replies with text, image, audio or document, no template needed. Outside it, only a Meta-approved template can go out, in the marketing, utility or authentication categories. The rule exists to protect users from unsolicited messages: with the window open the conversation flows; once it closes, there is deliberate friction.

What Meta charges

Since October 1, 2026, service messages (replies inside the window) get 1,000 free a month on each number, which do not roll over; from the 1,001st on they are charged per message, with no volume discount. Utility templates sent inside the window are no longer free and are charged from the first message. A conversation opened by a click-to-WhatsApp ad or the Page button gets 72 hours in which every message is free. Source: Meta's developer pricing page, checked in October 2026.

What it means for sales

If you wait for a customer to go cold and try to pick up with a loose message after 24 hours, you need a template — and a template that reads like an ad falls into the marketing category. On CRPRO, when the window of an official-API conversation has already closed, the screen tells you and offers the approved templates instead of open text.