After-hours enquiries, and the narrow version that actually works

An enquiry that arrives at 11pm is two different problems depending on how it arrives. If it came as a WhatsApp message, the clock that message started is still running the next morning, and a reply at 8am is an ordinary reply in your own words. If it rang your phone instead, almost nothing on this page applies, and the feature usually sold for that case, texting back the number that rang, is governed by a different half of Meta’s rules.

The clock a late message starts

Meta’s Service messages page, updated May 21, 2026 and read by us on 19 September 2026, states the mechanism that the 24-hour customer service window is named for:

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.

Run that against a real evening. A message at 11pm opens a window that does not close until 11pm the following day. A reply at 8am lands nine hours into it. Meta’s worked example on the pricing page marks both ends of that timer. The row for the customer’s message at hour 2 reads “This opens a 24 hour customer service window”, and the row at hour 26 reads “The CSW closes, which means you can no longer send non-template messages”, for the stated reason that “24 hours have passed since the user last messaged you”.

That is what makes after-hours messaging narrow rather than a staffing problem. Overnight is short, the window is long, and almost nothing arriving after you close is out of time by the time you open.

What you are allowed to send the next morning

Meta’s name for the reply you write inside that window is a service message:

Service messages are free-form messages that you can send to WhatsApp users during a customer service window

Free-form is the operative word, and the same page states the consequence: “service messages do not require pre-approval”. Outside the window the position inverts, in Meta’s words: “When the window closes, you can only send pre-approved template messages”.

So a reply at 8am to an 11pm enquiry is not a marketing operation, does not need a template registered in advance, and carries no approval delay. A reply on Thursday to a Monday enquiry is a different thing entirely. Meta’s pricing update page draws the line in one sentence:

Non-template messages (service message or Meta Business Agent message) can only be sent in an open 24-hour customer service window, which opens and resets with each user message. Thus non-template messages can only be used to respond - not reach out - to users

The asymmetry worth being precise about: once the window closes, you cannot reply either. Not by hand, not through any tool. The conversation waits until the customer writes again.

Where the free first-party version is already enough

WhatsApp’s own Business app has an after-hours feature, and its features page describes it as: “Respond automatically to messages received outside your business hours to set expectations and let customers know when you’ll be back.”

Read that carefully: it does less than the category implies. It sets expectations. It does not answer the question. An away message cannot tell somebody what a service costs, whether Saturday at ten is free, or whether you cover their postcode, because it is one fixed message written in advance.

What that page does not publish is any ceiling: no maximum length, no rate limit, no list of the scheduling options. WhatsApp’s help centre has a longer page on away messages, and we are not citing it, because a plain fetch of it returns no article text at all, so no quotation from it could be held to a saved copy. We have not tested those limits and we are not going to assert numbers on someone else’s account of their own app.

The honest split: if you only need to buy time, the away message is free and already on the phone in your pocket. If the enquiry needs a real answer that you have already written down somewhere, an auto-reply promising a reply tomorrow is a worse outcome than the answer.

What it costs, and the date that changes

Today, replying inside the window costs nothing. From the pricing page: “All non-template messages are free within an open customer service window.”

That ends on a published date, and what changes on 1 October 2026 covers the allowance and the delivery stop in full. Meta’s pricing update page says “Effective October 1, 2026 - Meta will charge on a per-message basis for all service messages”, and notes that “These messages have not been charged since November 1, 2024.” The rate is not a new rate card of its own: “By market, rates for service messages will be the same as the rates for utility and authentication messages.” There is no discount for volume, stated outright: “Meta will not offer volume tiers for service messages.”

One caution about rates, because the label on a rate matters as much as the rate. Meta’s rate cards are keyed by market, and the pricing page we read has no United States row at all: the United States sits alongside Canada inside a region Meta labels North America. Any figure handed to you as the American per-reply rate is a regional rate that somebody relabelled, and we are not going to print one, because Meta publishes no rate under that label. The countries Meta’s rate card does not name is the longer version of that problem.

Meta also meters an allowance on its own side: “Each business phone number has one shared free tier of 1,000 delivered service messages per month”, of which “Unused service messages in the free tier do not roll over”. That is Meta’s allowance on Meta’s platform, quoted here as a platform mechanic and not as an offer of ours. Without a payment method on the account the failure is silence rather than a bill: “Meta will stop delivering service messages as of when they become charged on October 1, 2026.”

Three limits the generic advice skips

• Opt-in comes first. The Service messages page is blunt: “you can only send messages to WhatsApp users who have opted in to receiving messages from you”. A window opening does not substitute for that.
• The reply can fail, and Meta says so. Under a heading it labels a known issue: “In rare cases, you may receive a message from a WhatsApp user but be unable to respond within the customer service window.” We have not measured how often, and Meta publishes no figure.
• Day three is a different product. The Business Messaging Policy allows a free-form reply only “within 24 hours of the last user message”, and says “You may only initiate conversations using an approved Message Template”. A chase two days later is template machinery, not a reply, and carries the approval step and the category Meta assigns you.

If the after-hours enquiries are calls

Then this is the wrong page and we would rather say so now. An after hour answering service, in the ordinary sense, is a person or a voice system picking up a ringing phone, and the three verbs a telephone answering service sells, none of which a messaging tool has is where that reader should go. mesej never messages anyone first and it cannot answer a phone at all. No channel is connected to it today either, so nothing here has answered an enquiry at any hour. Voice is a different product with different failure modes, and a wrong answer spoken aloud in real time cannot be reviewed before it lands.

If most of what arrives after closing rings rather than writes, buy a voice answering service.

The narrow version that works

One thing, precisely: an enquiry that arrived as a message gets answered inside the window that message opened, from notes that were written down before anyone asked. That is small, and it is the whole of what the 24-hour rule actually permits. Everything wider than it is either a template operation or a phone line.

Judging a tool by what its platform documents rather than by what its landing page claims is the same exercise as picking review management software.