WhatsApp 24-Hour Customer Service Window Explained

The WhatsApp 24-hour customer service window is the rule that shapes all business messaging on WhatsApp: for 24 hours after a customer's last message, your business can reply freely — any text, image, or document. When the window closes, free-form messaging stops, and only an approved message template can restart the conversation. Every support workflow, AI agent, and notification strategy on WhatsApp is designed around this clock.

How the window opens and closes

The window opens the moment a customer messages your business number — any message counts, even a single emoji. It runs for exactly 24 hours from that message, and every new customer message resets it to a fresh 24 hours. Your business's own messages do not extend it. The window is per customer, per number: one customer's window can be open while another's has closed.

What you can send inside the window

Inside the window, anything goes: free-form replies (called service messages), media, documents, and even utility templates. This is where AI agents live — an agent answering questions, qualifying leads, or handling support is working inside open windows. Note the pricing change: since October 1, 2026, those in-window service messages are billed per message by Meta after a free tier of 1,000 per number per month — free-form no longer means free, as the

per-message pricing guide explains.

What happens when the window closes

After 24 hours of customer silence, your free-form replies are blocked — the API simply will not deliver them. The only way back in is an approved message template from the right category: a utility template for an order update or reminder, or a marketing template for an offer (to customers who opted in). The customer's reply to that template re-opens a fresh 24-hour window. This is why templates are not bureaucracy — they are the re-entry mechanism.

Support lead: “We stopped losing threads when we started sending the reminder template at hour 23.” The window rewards businesses that follow up before it closes, not after.

Designing around the window

Answer fast while the window is open — an AI agent helps here because it replies in seconds, day or night. Before the window closes on an unresolved issue, send a useful message (a summary, a next step, a question) that invites a reply and resets the clock. For conversations that must continue later, schedule the right template in advance rather than discovering the window closed. And keep the templates themselves honest: the

templates guide covers which category each message belongs in.