The WhatsApp 24-hour window, and what it actually costs you
In short
The 24-hour customer service window opens each time a customer messages you. Inside it you can reply freely, with any content, at no charge and with no monthly cap. Once it closes, the only way to reach that customer is an approved template message, which Meta bills per message — around RM0.30–0.45 for marketing and RM0.056 for utility in Malaysia.
Sellers who move to the WhatsApp Business Platform usually expect the bill to track how busy they are. It does not. It tracks how often they start conversations, because the rule that governs cost is not volume — it is who spoke last, and how long ago.
How the window works
Every inbound message from a customer opens (or re-opens) a 24-hour window on that conversation. Inside it your team, or your AI agent, can send whatever the conversation needs — text, images, a voice note, ten messages in a row — for free, with no cap.
When 24 hours pass without a new message from the customer, the window closes. Free-form messages are then rejected by the API. Your only route back in is a template that Meta approved in advance, and sending one is a billable event.
A template sent successfully does not re-open a free window by itself — the customer replying is what re-opens it. That is the detail that catches out teams who assume a broadcast buys them a day of free messaging.
Where the money actually goes
Marketing templates are the expensive category and the one most sellers over-use: a promotion sent to ten thousand contacts is ten thousand billable messages, whether or not anyone replies. Utility templates — order confirmed, parcel shipped, appointment tomorrow — cost a fraction of that and are usually the ones customers actually want.
So the cheapest WhatsApp operation is not the quietest one. It is the one where customers start most of the conversations: ads and website widgets that get people to message first, then support handled inside the free window, with templates reserved for genuinely useful moments.
What this means for your team's shifts
A window that closes while everyone is asleep is a real cost, not just a slow reply. A customer who messages at 11pm and gets an answer at 10am the next morning has cost you nothing in fees — but a customer who messages at 11pm and gets an answer at noon the following day has to be re-engaged with a paid template, if they have not bought elsewhere by then.
This is the practical case for automation that answers at night: not that it replaces the team, but that it keeps conversations inside the window where replies are free and intent is still warm.
Frequently asked
- Does the 24-hour window reset every time I reply?
- No. Only an inbound message from the customer opens or extends the window. Your own replies do not extend it, which is why a thread can go quiet and close even while your team is still typing into it.
- What happens if I try to send a normal message after the window closes?
- The API rejects it. You will see a failure rather than a silent drop, and the only way to reach that customer is an approved template message, which is billed per message.
- Does sending a template re-open the free window?
- Not by itself. The customer replying to it does. Teams often assume a broadcast buys 24 hours of free messaging for everyone it reached — it does not, and only the people who reply become free to talk to.
- Is there a monthly cap on free service replies?
- No. Under per-message pricing, replies inside the 24-hour window are free and uncapped — which is why a support-heavy store can run at close to zero message cost while a promotion-heavy one cannot.
Read in中文Bahasa Malaysia