There are two clocks, and everything depends on which one you are on
Every message your business sends on the WhatsApp Business Platform falls on one side of a line. When a customer messages you, a 24-hour customer service window opens. Inside that window you can reply with free-form messages — text, images, documents, whatever the conversation needs — and Meta does not charge for them. Outside it, you cannot send free-form anything. You can only send a pre-approved template.
That single rule explains most of the confusion operators run into. Your receptionist replies to a patient at 9am and everything is fine. She replies to the same patient at 11am the next day and the message silently fails, because the window closed. The fix is never to fight the window; it is to design your flows so the important message either lands inside a window somebody opened, or is a template you already had approved.
The commercial side changed on 1 July 2025, when Meta moved from conversation-based pricing to per-message pricing and deprecated the old model. You are charged when a template message is delivered, at a rate that depends on the template category and the recipient's country code. Separately, since 1 November 2024, service conversations — the ones a customer starts — are free for all businesses. There is also a 72-hour free entry point window when a person reaches you through a Click to WhatsApp ad or a Facebook Page call-to-action button, during which any message type costs nothing.
Template categories are a pricing decision disguised as paperwork
Templates come in three categories, and choosing the right one is not an administrative formality — it decides what you pay and how much tolerance you get.
| Category | What belongs there | When you are charged |
|---|---|---|
| Utility | Something the customer already asked for or transacted for: order confirmations, appointment reminders, dues notices, delivery updates, receipts. | Charged when sent outside an open customer service window. Free inside one. |
| Marketing | Anything promotional: offers, new-service announcements, re-engagement, catalogue pushes. | Always charged, window or no window. |
| Authentication | One-time passcodes and login verification only. | Charged at its own rate, which differs by country. |
The temptation is obvious: dress a promotion up as a utility template so it costs less and gets sent more freely. Do not. Meta re-categorises templates it judges to be miscategorised, and a business that keeps doing it earns exactly the reputation signals described further down this page. The honest version is cheaper anyway, because utility messages people actually wanted get replies, and replies open free windows.
Opt-in is a rule, not a courtesy
The WhatsApp Business Messaging Policy is unusually blunt about this. You may only contact people on WhatsApp if they have given you their mobile phone number and you have received opt-in permission confirming that they wish to receive subsequent messages or calls from you. Both conditions. Having somebody's number because they walked into your clinic is not consent to message them about a weekend offer.
- Collect opt-in where the customer can see what they are agreeing to — the intake form, the booking screen, the receipt footer — and store the timestamp and the wording they saw. If you are ever asked, you will need it.
- Take separate opt-ins for separate things. Appointment reminders and marketing offers are not the same permission, and a customer who wants one and not the other should be able to say so.
- Put opt-out instructions in the messages themselves and honour them the same day. A person who cannot leave will report you instead, and a report costs far more than an unsubscribe.
- Never buy or scrape a list. Bought numbers have no opt-in by definition, and they are the fastest known route to a restricted number.
What actually gets replies
Across the messaging flows we build into clinic and school software, the pattern is consistent and slightly boring: messages that carry a fact the customer needs get read and answered; messages that carry an ambition the business has get ignored.
- Write in the language the customer wrote to you in. In Kerala that means Malayalam replies to Malayalam messages, and in the Gulf it means Arabic to Arabic — not an English template with a translated footer.
- Put the useful thing in the first line. On a phone, a WhatsApp notification shows a couple of lines. 'Dr Nair is running 40 minutes late, your new time is 4:40pm' works. 'Dear valued patient, we hope this message finds you well' does not.
- Give a reply a job to do. 'Reply 1 to confirm, 2 to reschedule' both gets you an answer and opens a 24-hour window you can use.
- Send at human hours in the customer's own time zone. India and the UAE are ninety minutes apart, and a reminder that arrives at 11:30pm reads as spam regardless of how useful it is.
- Keep one thread per customer. Routing billing, appointments and support to three different numbers turns a conversation into an inbox, and inboxes get muted.
What gets you blocked
Two mechanisms decide whether your number keeps working, and both are driven by how people react to your messages rather than by any content review.
The first is template quality rating, computed from usage, customer feedback and engagement. Meta grades each template green, yellow or red — high, medium and low quality — with new templates starting unknown until there is data. Sustained negative feedback or low read rates move a template down, and a template can be paused or disabled entirely; a template whose status is anything other than approved simply cannot be sent.
The second is your messaging limit: the number of unique WhatsApp users you can message outside a customer service window in a rolling 24 hours. New business portfolios start at 250. Verifying your business, or delivering 2,000 messages outside service windows to unique users within a 30-day moving period using high-quality templates, lifts you to 2,000; beyond that the tiers move automatically to 10,000, 100,000 and unlimited if quality holds and you use enough of your current limit. It moves the other way too — a number whose quality rating has been flagged for seven days is dropped a level.
A starting setup that survives contact with reality
- Four or five utility templates that cover the things you send every day, approved before you need them rather than the afternoon you do.
- One marketing template, sent rarely, to people who opted in to marketing specifically.
- Opt-in captured at the point of first contact, with the wording and the date stored against the customer record.
- A reply path that a human actually watches during working hours. An automated first reply that leads nowhere is worse than a slow human one.
- Your own WhatsApp Cloud API credentials, so the per-message cost you pay is Meta's rate rather than a reseller's markup on it.
The businesses that do well on WhatsApp are not the ones sending the most messages. They are the ones whose customers reply.
None of this requires a large team. It requires deciding, once, that WhatsApp is an operational channel with rules rather than a free broadcast tool — and then building the flows around the 24-hour window instead of against it.
Sources
Every external claim in this article links to the page it came from, with the date we last checked it. Rules and prices move — if you are relying on one of these, open the source.