Two rules govern almost everything about WhatsApp messaging economics and freedom. Neither is complicated; both are routinely misunderstood, usually in the direction of leaving money and flexibility on the table.
The 24-hour customer service window
When a customer messages you, a 24-hour window opens. Inside it you can send free-form messages — any content, no template, no pre-approval. When it closes, you can only send an approved template until they message again.
The window resets with every inbound message. An active conversation stays open indefinitely as long as the customer keeps replying.
Why this shapes support workflow
A conversation left overnight can drift past the boundary, at which point the natural reply becomes impossible. Prioritising conversations by time remaining, rather than by arrival order, prevents this — and every support tool worth using can show you that number.
Practical consequences of the window
- Answer within the window or you lose the ability to reply freely.
- Keep an approved "still working on this" template for cases that outlive it.
- Asking a question near the end of a window risks the answer arriving after it closes.
- Anything you need to send with unpredictable content should go while the window is open.
Free entry points
Certain routes into a conversation come with a free window — most importantly click-to-WhatsApp advertisements and call-to-action buttons on Facebook pages. When someone arrives through one of these, the resulting conversation carries no conversation charge for a defined period.
This is not a minor discount. For a business that advertises, routing ad traffic into WhatsApp rather than to a landing page can change the economics of the whole channel — you get a conversation, a consented contact and a free window, instead of a bounce.
Designing around both
- Create entry points everywhere. Website button, QR on packaging and receipts, links in email footers, click-to-WhatsApp in campaigns. Every one shifts a conversation from your cost column to a cheaper one.
- Give people a reason to message first. "Message us for stock in your size" is cheaper and converts better than broadcasting availability.
- Do useful work inside open windows. If a window is open, that is when to answer questions and confirm details rather than sending a template later.
- Sequence around expiry. If you know a window closes tomorrow and you will need to reach them, either resolve it now or ensure a template exists.
A common misunderstanding
The window is not permission to market. Free-form messaging inside a service window is for the service conversation — answering what they asked. Using an open support window to push a promotion is both a policy problem and a reliable way to get blocked by someone who came to you with a question.
Watch the ratio
Track what share of your conversations are customer-initiated versus business-initiated. If it is heavily weighted to business-initiated, you have both a cost problem and, usually, an engagement problem — because a programme where customers never start the conversation is one they are tolerating rather than using.