The WhatsApp 24-hour window, explained in plain English
One rule decides what you can send a customer on WhatsApp and how much it costs. Once you understand it, half the confusion around the API goes away.
Key takeaways
- Every time a customer writes to you, a 24-hour window opens and you can reply freely.
- Each new message from the customer restarts the 24 hours.
- Outside the window you can only send an approved template.
- Replying quickly keeps conversations inside the cheaper, more flexible window.
If you use WhatsApp through the official Business Platform, sooner or later you will see a message like "window closed" or "use a template". It feels like a technical restriction. In practice it is a simple rule, and it protects your customers from spam.
The rule in one sentence
When a customer sends you a message, a 24-hour customer service window opens. During that time you can reply with anything: text, photos, audio, documents. When the 24 hours run out, you can only write to them using a template approved by Meta.
Every new message from the customer resets the clock to 24 hours. A real back-and-forth conversation never "runs out".
What is a template?
A template is a message you write in advance and submit for approval. It can include variables, like the customer's name or an order number. Meta sorts templates into three categories:
- Marketing: offers, news, invitations to come back.
- Utility: updates about something the customer asked for, like order confirmations, delivery updates or payment reminders.
- Authentication: one-time codes for logging in.
Templates are how a business starts a conversation. They are also how you follow up after a customer goes quiet for more than a day.
How the window affects what you pay
Since July 2025, Meta charges per delivered message instead of per conversation. The basics:
- Messages customers send to you are never charged.
- Template messages are charged by category, and the price depends on the customer's country. Marketing is the most expensive.
- Service replies inside the window come with a monthly free allowance per business number. Beyond it they are billed.
- When a customer arrives from a Click to WhatsApp ad, your replies are free for a limited period.
Meta adjusts these rules from time to time. In October 2026, for example, utility templates sent inside an open window stopped being free. Always check Meta's official pricing page before planning costs.
Three habits that save money and headaches
Reply fast. The quicker you answer, the more of the conversation happens inside the window, where you can write naturally instead of hunting for the right template.
Ask one question at the end. "Would you like me to reserve it?" invites the customer to reply, which keeps the window open while they decide.
Keep a few good templates ready. One to follow up on a quote, one to confirm an order, one to bring back customers who have not bought in a while. Approved and waiting, they save you from panic when a window closes at the worst moment.
The window is not your enemy
It is easy to see the 24-hour rule as a limit. Think of it the other way around: WhatsApp is the one channel where customers still read almost everything, precisely because businesses cannot message them whenever they like. Respect the rule, reply quickly and send templates people actually want, and the channel keeps working for you.
Frequently asked questions
What happens if I miss the 24-hour window?
You can still contact the customer, but only with a pre-approved template message, which is billed by category. A common approach is a short utility or marketing template that invites the customer to reply, which reopens the window.
Are messages inside the window free?
Customer messages to you are always free. Meta also gives each business number a monthly allowance of free service replies, after which service messages are billed. Template messages are billed by category. Check Meta's pricing page for your country's current rates.
Does the window apply to the free WhatsApp Business app?
No. The 24-hour customer service window is a rule of the WhatsApp Business Platform (the API). The free app works differently.
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