Almost every confusing thing about the WhatsApp Business Platform traces back to one rule: you may send free-form messages to a customer only within 24 hours of their last message to you. Meta calls this the customer service window.
What opens the window
An inbound message from the customer. Any inbound message — a reply to your template, a question from a Click-to-WhatsApp ad, a plain hello. The clock restarts from the most recent inbound message, not the first one.
What you can send while it is open
- Plain text.
- Media — images, documents, video, audio.
- Interactive messages such as buttons and lists.
- Templates too, though you rarely need them here.
What happens when it closes
Free-form sends start failing. The only way to reach that person again is an approved message template. This is why template approval is not an optional nicety you get to later — it is the mechanism for re-opening a conversation, and it takes time you need to have already spent.
How this changes the way you staff support
A customer who messages at 6pm and gets an answer at 11am the next day is still inside the window. A customer who messages on Friday evening and hears nothing until Monday is not — and that reply now costs a template and looks like a marketing message. The practical fix is an away message so the window is at least acknowledged, and honest SLA targets your team can actually hit.