The WhatsApp 24-hour window, templates, and opt-in, explained

"Do you have anything Saturday?" That message reaches a salon owner's WhatsApp at 6 p.m. on Friday. (The case is invented, but a typical one.) The weekend rush swallows her Saturday, and the message waits. On Monday morning she writes back, and the platform will only accept an approved template. The customer booked elsewhere days ago.

That refusal is not a bug. It is Meta's 24-hour rule.^[1] The rest of this post walks through it: the window, the templates that work outside it, the consent rules underneath, and how Meta now charges. We read Meta's own documentation, and we give the date we read it, because parts of it change on a schedule.

We are not lawyers, and this is not legal advice. Where we describe a rule, it is what Meta's documents say. Where laws in your country matter, Meta's own page says to follow applicable laws, and we leave it there.

Free-form or template: the clock decides

On Meta's business platform (the API that software connects to, not the free app on a phone), a message to a customer is one of two things.^[1][2]

A free-form message. Text, an image, a voice note, buttons, or a location request, written on the spot. Meta calls these service messages.

A template message. A message whose wording you submitted in advance and Meta approved. It can have blanks for a name, a time, or an order number, but the shape is fixed.

Which one you may send depends on whether a customer service window is open.

How the window works

Meta's documentation puts it in one sentence: when a WhatsApp user messages you or calls you, a 24-hour timer called a customer service window starts.^[1] If the same person contacts you again before it runs out, the timer restarts.^[1]

Three consequences follow.

The customer opens it. Meta ties the window to the customer's message or call, and does not describe a business message starting one.^[1]

It runs from their latest message. Meta describes the timer as restarting when the customer contacts you again, and says nothing about your own replies extending it. A customer who writes at 6 p.m. on Friday gives you until 6 p.m. on Saturday, unless they write again.^[1]

Inside it, you are free. The documentation says you can send any service message type without pre-approval.^[1] The salon owner could have replied in her own words, with photos of the free slots and a button to confirm.

Once the window closes, Meta's text is just as direct: you can only send pre-approved template messages.^[1] The templates overview says it again: templates are the only type of message that can be sent outside a customer service window.^[2]

Here is the salon owner's week as a timeline.

Meta's page carries one caveat that is worth repeating. In rare cases you may receive a message from a user and be unable to respond within the window.^[1] Meta does not explain which cases, so we will not guess.

Templates, and what they are for

A template belongs to one of three categories. Meta describes marketing templates as covering goals from awareness to driving sales, utility templates as follow-ups to something the customer did or asked for, and authentication templates as verifying a user's identity.^[2][3] The category matters twice: for what the wording may contain, and for what you pay.

Templates go through review. Meta's page says templates undergo automatic review on creation, that approved ones show as APPROVED, and that a rejected one cannot be sent.^[2] Its status guide adds that review can take up to 24 hours.^[2] Plan for that. A template is not something you write at the moment of need.

There is also a quality system. Meta rates templates based on usage, customer feedback, and engagement, and a template that performs badly can be paused or disabled.^[2] In practice, if customers keep blocking or reporting a message, you lose the ability to send it.

Back to the salon. On Monday she cannot write "Sorry for the late reply, we have Thursday slots." The window shut on Saturday evening, so only an approved template is allowed.^[2] What she can do is send an approved template written as a follow-up to the customer's own question. Meta decides which category it counts as, and the category sets the price. If the customer answers, a new window opens, and she is back to free conversation.

Opt-in: the rule under the other two

Windows and templates settle how you may message. Opt-in settles whether you may.

Meta's opt-in page says businesses must clearly state the business name a person is opting in to hear from, and must comply with applicable laws.^[4] It lets you collect consent in several ways, such as by SMS, on a website, by phone, or on paper, provided the method meets those requirements.^[4] It also expects clear instructions for opting out of specific categories of message, and that you honor such requests.^[4]

The WhatsApp Business Messaging Policy, which the page itself shows as last updated on September 23, 2026, is blunter.^[5] You may contact people on WhatsApp only if they have given you their mobile number or username and you have received opt-in permission from them. It also requires that you do not mislead, spam, or surprise people, and that opt-outs are honored.^[5]

Consider what this means for the 24-hour window. A customer who messages you first has plainly reached out, yet Meta's service-message page still states that you can only send messages to users who have opted in.^[1] Our reading, and the safest one: do not treat the window as a license for everything. Collect consent clearly, record it, and respect "stop".

What it costs now, and why the date matters

Meta used to bill per conversation. It moved to per-message billing on July 1, 2025.^[6] As of October 2, 2026, the pricing page says:

• You are charged only when a template message is delivered, and the rate depends on the template's category and the recipient's country calling code.^[6]
• Non-template messages inside an open customer service window are free.^[6]
• Utility templates sent inside an open window are free.^[6]
• Messages of all types within a 72-hour free entry point window, started through a Click to WhatsApp ad, are free.^[6]
• Utility and authentication messages get lower rates as monthly volume rises, counted across all accounts in a business portfolio.^[6]

The prices are a moving target. The page says Meta may adjust them on the first day of each quarter (January, April, July, October), with notice ranging from one month for rate changes to six months for changes to the pricing model.^[6] The same page lists rate-card updates dated October 1, 2026 for some markets, so the table it calls current may already be out of date.^[6] We deliberately quote no per-message price here. They differ by country and category, and some will be wrong by the time you read this. Use Meta's current rate card for your market.

Designing an automated reply around these rules

If a business wants software to answer WhatsApp messages, the rules above translate into a short design.

Reply freely inside the window. When a customer writes, an automated system can answer straight away in free-form text, as long as the window is open. This is the cheap, conversational part, and it is where speed matters most.

Use an approved template outside it. Once the window has closed, the system can send only a template, and each delivered template is a billable event. A follow-up should therefore be a deliberate, pre-approved, ideally useful message, not a nudge sent to everyone.

Message only people who have opted in. Cold outreach by WhatsApp to a purchased list cannot meet the opt-in requirement above. Store the consent trail: who agreed, to what, under which business name, and when.

Keep a human reachable. The policy says businesses may use automation when responding inside the window, but must also have prompt, clear, and direct escalation paths such as in-chat transfer to a human, phone, email, web support, or an in-store visit.^[5] A system that traps people in a loop is not just bad service. It would likely be out of line with that policy.

Say it is automated. We did not find a disclosure requirement in the pages we read. We would still do it, because people deserve to know whether they are talking to a person.

Watch the quality signals. Poor-quality templates can be paused,^[2] and Meta says people can block or report businesses and that low-quality accounts can be rate-limited.^[4] A system that sends too much will weaken itself.

What we do not know

We did not read the full, current text of every policy page, and Meta reorganizes its documentation often. Pages that we fetched had moved or redirected, and some summaries we relied on came from a tool that condenses the page for us. Check the live pages before building anything that depends on a detail: the exact opt-in wording that is acceptable in your country, your market's rate, and any new rules about automated assistants.

We also did not test how any particular software provider handles a closed window in practice. Providers may differ in how they show it.

Where Gonzo comes in

Gonzo Digital builds WhatsApp-capable reply systems for businesses outside India, with these rules designed in: replies inside the window, templates outside it, a consent record, and a route to a human. Nothing has run live yet. The price is fixed and the scope is agreed before you commit. If that is useful, talk to us.