Your reply on WhatsApp has a 24-hour deadline
An enquiry arrives at seven on Friday evening. Somebody reads it Monday morning, types a proper answer, presses send, and the message does not go anywhere.
Nothing is broken. The account is fine, the number is fine, the customer is sitting there with the phone in their hand. The business simply answered sixty-two hours after the question, and on this platform an answer has a shelf life.
This is Meta's rule for businesses messaging through the WhatsApp Business Platform. It is not a law, and it is not how messaging works in general. It is one company's rule about one channel, and it catches out roughly everybody the first time.
The clock starts when the customer speaks
Meta's documentation states the mechanism in two sentences:
"When a WhatsApp user messages you or calls you, a 24-hour timer called a customer service window starts. If the user messages or calls you again before the timer expires, the timer resets to 24 hours."
Meta, Service messages
While that window is open, a business can write whatever it likes. Meta calls these service messages and says they "do not require pre-approval - you can compose and send them as needed in response to a WhatsApp user's message or call."
Note what starts the timer. A message from the customer, or a call from the customer. Meta's calling documentation adds that the window starts or refreshes "When a WhatsApp user calls you, regardless of if you accept the call or not" - so a missed call from a client buys you a day to write back.
And note what is absent from that sentence, because the absence is the whole article.
Your own replies do not move the deadline
The rule names one thing that resets the timer: the user messaging or calling again. A business replying is not in the list.
Meta does not publish an explicit "these things do not count" list, so read the definition for what it leaves out. Four things can happen on a thread: the business sends a template, the customer replies to that template, the customer writes in an ongoing conversation, or the business replies to the customer. The definition names only "when a WhatsApp user messages you or calls you", so the timer starts in the second and third cases and in neither of the others.
Both of those are the customer doing something. Neither of the business's own actions makes the list.
The practical consequence is unintuitive enough to be worth stating flatly. A customer writes at nine on Monday morning. Over the next day you send eleven messages, they read all of them, they answer none. At nine on Tuesday the thread closes, and your twelfth message needs approval from Meta before it can be delivered.
Twenty-four hours of your typing does not extend anything. Only theirs does.
After it closes you can still write, in words approved in advance
The window shutting is not a ban. It is a switch from writing to choosing.
Meta: "While the window is open, you can send any of the service message types listed below to the user. When the window closes, you can only send pre-approved template messages." Its template documentation puts the same thing the other way round: "Template messages are the only type of message that can be sent to WhatsApp users outside of a customer service window."
A template is a message you wrote earlier, submitted to Meta, and had approved, with blanks for the details that change. "Hi {{1}}, your appointment on {{2}} at {{3}} is confirmed." Fill the blanks, send the template, and it goes through whatever the clock says.
So the answer to "we replied on Monday and it did not arrive" is not "you cannot reply on Monday". It is that Monday's reply had to be a sentence you wrote and submitted last month, and nobody knew to write it.
| Inside the window | Outside the window | |
|---|---|---|
| What you may send | any service message type, composed on the spot | pre-approved templates only |
| Approval needed | none | yes, before sending |
| Who opens it | the customer, by messaging or calling | nobody; you wait to be spoken to |
| What a free-form message does | delivers | fails with error 131047 |
| Cost of a plain text message | free | not available at any price |
A template is a knock, not a door
The obvious move once you understand templates: send one, and carry on conversing normally afterwards.
That is not what happens. Of the four scenarios above, "a template is sent by the business to the user" is precisely the one the definition leaves out. Sending a template does not open the window; the window opens when the person replies to it. Meta's own definition of its messaging limits points the same way, counting the people "your business can deliver messages to, outside of a customer service window" - a business writing first is outside the window by definition.
Which means every business-initiated conversation on this platform has the same shape. You get one approved sentence. If it earns an answer, you have a day of normal conversation. If it does not, you are back to choosing from your approved sentences, and the customer has no idea any of this is happening.
The error has a number, and it is not always honest
When a free-form message goes out after the window has closed, Meta returns error 131047 with the text "More than 24 hours have passed since the recipient last replied to the sender number", and the recommended action: "Send the recipient a template message instead."
Worth knowing the number, because it is what your integration will show you and what you will end up searching for. Also worth knowing that the number can lie. A user of an open-source helpdesk reported in February 2026 getting 131047 even though the customer had just written and the window should have been open; the same message sent directly through the Cloud API went through, and the cause turned out to be the helpdesk's hosting rather than anything at Meta.
So 131047 means "this send was rejected as being outside the window". It does not always mean the window is genuinely shut. Check the timestamp of the customer's last message before rebuilding anything.
There is a separate failure worth knowing about, which Meta lists as a known issue on its service messages page: "In rare cases, you may receive a message from a WhatsApp user but be unable to respond within the customer service window."
Why the rule feels invented
Plenty of business owners read all of the above and are certain it is wrong, because they answer customers on WhatsApp at their own pace and nothing ever fails.
They are right about their own experience. Meta draws a line between the WhatsApp Business app on a phone and the Cloud API that software connects to:
"The 24-hour customer service window restriction applies to messages sent via Cloud API. Messages sent from the WhatsApp Business app are not subject to the customer service window and do not create, extend, or affect Cloud API conversation windows or Cloud API pricing."
Meta, onboarding WhatsApp Business app users
Same phone number, same customer, same thread on screen. The rule depends on which channel the letters left through. This is the single most useful sentence to have in hand when you connect a booking system or a helpdesk to a number that somebody has been answering by hand for two years: the habits that worked on Friday stop working on Monday, and no setting caused it.
Approval takes up to a day, and the category is not yours
Two things about templates that decide whether this is a small problem or a recurring one.
The first is timing. Meta says of template review: "It can take up to 24 hours for an approval decision to be made." A template written in response to a conversation that has already gone cold arrives about a day after it was needed. Templates are pantry items. You stock them before the week starts.
The second is classification, and it surprises people who thought they were writing an operational message. Meta categorises templates, and mixed content lands in the marketing bucket: "Templates with mixed content (for example, both utility and marketing, such as an order update with a promo or a feedback survey with promotional content)". Add a discount line to an order update and the whole template becomes marketing, with marketing's pricing and marketing's restrictions.
Meta also reclassifies existing templates on its own, with "A 1-day advance notice is provided before the template category is updated to marketing", and a window of 60 days to ask for a review. Somebody in Meta's developer community described exactly this in November 2025: "whatsapp templates are being marked as marketing templates while they only use to send updates no marketing content is being used, tried to request review but the review got rejected".
Rejections are their own genre: a template approved after changing a single word, a rejection that arrives as "INVALID_FORMAT" with no further detail. Budget for a second round.
What the window costs
Since 1 July 2025 Meta charges per message rather than per conversation. The pricing that matters for this article is about where the message falls, not what it says.
Inside an open window, anything you compose yourself is free: "All non-template messages are free". Utility templates delivered inside an open window are free too. Marketing templates are charged wherever they land - "All marketing template messages are charged" - and outside the window a template is the only thing you can send at all.
Two more numbers worth having. Answer an enquiry that arrived from a Click to WhatsApp ad within the first 24 hours, and the ordinary clock is replaced by a longer one: "FEP windows remain open for 72 hours. While open, you can send any type of message to the user at no charge." Those 72 hours run from your reply rather than from their message, so missing the first day forfeits the whole thing. And a new business portfolio can message only 250 unique people outside a window per rolling 24 hours, a limit that rises through tiers as the account scales. Answering inside windows is not capped by that number; speaking first is.
Read together, the pricing says something clear about the design. Replying to customers costs nothing. Starting conversations is metered, approved and rate-limited. Whether you like it or not, that is the shape you are building inside.
What to check in your own setup
Find every message your business sends first. Appointment reminders, order updates, "your document is ready", review requests, anything that fires on a schedule rather than in reply. Each of those is outside a window by definition, and each needs an approved template rather than a sentence your workflow composes.
Look at how long answers actually take. Not the average - the tail. Enquiries that arrive on Friday evening, over a holiday, or during the hour your one person is with a client. Those are the ones that land outside the window, and they are also the ones where the customer is already unimpressed. Slow replies cost bookings on their own; here they also change what you are technically allowed to say. That is the same arithmetic behind reminders that reduce no-shows.
Write the templates before you need them. Reschedule, follow-up, document chase, payment reminder, we-tried-to-reach-you. Approval takes up to a day and sometimes two rounds, so the stock is built on a quiet afternoon.
Keep utility and marketing apart. One promotional line inside an order update reclassifies the whole template. If the message exists to inform, let it inform.
Check what your tool shows when a send fails. Some integrations mark the message sent and quietly drop it. If a failed reply looks identical to a successful one on your screen, you have a failure with no error in it, and the first person to notice will be the customer.
Decide who answers, and inside what time. A window is only a problem for a business that cannot reliably respond within a day. Where an assistant answers the routine questions, most conversations never approach the deadline at all.
When this stops being a settings question
For one number, one person answering, and enquiries during working hours, the checks above are the whole job. Stock a few templates, answer within the day, and the window never becomes visible.
It turns into a design question the moment messaging stops being one person typing. A booking system that confirms, reminds and reschedules; a helpdesk that routes; a form on the site that starts a thread. Each of those wants to speak first, at a time of its choosing, in words a machine assembled - which is the one thing the platform does not allow. Building that properly means deciding, up front, which messages are templates, which are replies, and what happens to a conversation that goes quiet for a day.
Working out which of those two situations you are in is what a process audit settles: $299, three business days, and a written map of which of your messages need approval before anyone can send them.