WhatsApp 24-Hour Session Window Calculator
Enter when a customer last messaged you and see exactly when the free-form messaging window closes — and whether you need an approved template message right now.
Times use your browser's local timezone.
How the 24-Hour Window Works
WhatsApp's Business Platform gives you a 24-hour customer service window after every inbound message from a customer. Inside that window, you can reply with any free-form (session) message — no pre-approval needed.
Once 24 hours pass without a new message from the customer, the window closes. To reach them again, you must send a message template that was pre-approved by Meta. If the customer replies to that template, a new 24-hour window opens.
This rule exists to stop businesses from messaging people out of the blue — it keeps outreach tied to a customer-initiated conversation unless you use an approved template.
Send Messages via the API
Send free-form replies inside the window, or trigger a template message outside it — both from the same API.
Try Free on RapidAPI →