How to handle the 24-hour window on the WhatsApp Business API
On the WhatsApp Business API, every time a customer messages you a fresh 24-hour "customer service window" opens. Inside it you can reply with free-form text, images, buttons, lists and interactive messages at no messaging charge. Outside it, you can only re-open the conversation with a pre-approved template. Getting this right is the single biggest lever on both your reply quality and your monthly WhatsApp bill. This tutorial walks through exactly how the window works, how to check whether it's open, and how InfiQ handles the switching between free-form and template messages for you.
What you'll do
The 24-hour service window opens each time a customer messages you and lets you send free-form replies at no messaging charge. Once it closes, only a pre-approved template can re-open the conversation. InfiQ tracks each contact's window and automatically sends free-form inside it and a utility/marketing template outside it, so you never lose a message or overpay.Step 1 — Understand what the 24-hour window actually is
The 24-hour window (Meta calls it the customer service window) is a free service window, not a billing unit. It exists so businesses can respond to customers conversationally. The moment a customer sends you any message — a text, a button tap, a reaction, a media file — a 24-hour clock starts. Inside those 24 hours you may send any type of message you like without it counting as a template send. Crucially, since Meta moved off per-conversation billing on 1 July 2025, WhatsApp now bills per delivered message by category (marketing, utility, authentication). Service replies sent inside the open window carry no messaging charge. This means the window is about what you are allowed to send and whether it's free — not a 24-hour bucket you pay for once.
- Window opens: on the customer's inbound message
- Window resets: every subsequent inbound message restarts the full 24 hours
- Free-form allowed only while the window is open
- Outside the window: only pre-approved templates can reach the customer
Step 2 — Check whether the window is open before you reply
Before sending, you (or your automation) need to know the state of each contact's window. In the InfiQ shared inbox this is visible at a glance: an open window is clearly indicated on the conversation, and agents can type a normal reply. When the window has expired, the free-form composer is disabled and InfiQ prompts you to pick an approved template instead. If you are building on the API directly, the signal comes from the timestamp of the last inbound message on that contact — anything within the last 24 hours means the window is open. InfiQ stores this last-inbound timestamp per contact so the correct send path is chosen for you, whether the message is sent by a human agent or by an automated flow.
- In the inbox: a visible window indicator and an enabled reply box
- Via API: compare now vs. the contact's last inbound message timestamp
- InfiQ tracks last-inbound per contact so you don't compute it yourself
Step 3 — Reply free-form while the window is open
When the window is open, send everything conversationally. Free-form messages inside the window can include plain text, images, documents, audio, location, quick-reply buttons, and interactive list/CTA messages — none of which need pre-approval and none of which incur a messaging charge as a service reply. This is where you should do the real work of the conversation: answer the question, share the invoice, confirm the order, collect the missing detail. A common and costly mistake is sending an approved template when the window is still open — that turns a free service reply into a billable utility or marketing message for no reason. InfiQ defaults to free-form whenever the window is open precisely to avoid this.
- Use rich free-form: text, media, buttons, lists, interactive replies
- Do the substance of the conversation here while it's free
- Never fire a template if a free-form reply would reach the customer
Step 4 — Re-open a closed window with the right template
Once 24 hours pass with no inbound message from the customer, the window closes and free-form messages will no longer be delivered. To reach that customer again you must send a message built from a template you submitted to Meta and had approved. Choosing the correct template category matters for both approval and cost: use a utility template for transactional, expected messages tied to an existing order or account (order updates, appointment reminders, payment confirmations); use a marketing template for promotions, offers and re-engagement; use an authentication template for one-time passcodes. Sending a marketing template where a utility template would fit inflates your bill, and using the wrong category is a frequent cause of rejections. When the customer replies to your template, a fresh 24-hour window opens and you're back to free-form.
- Utility — order updates, reminders, confirmations tied to an account
- Marketing — promotions, offers, re-engagement
- Authentication — one-time passcodes
- Their reply to your template re-opens a fresh 24-hour window
Step 5 — Let InfiQ automate the switching, then monitor
You should not be tracking 24-hour clocks by hand across thousands of contacts. Configure InfiQ so that outbound messages from your flows check the window automatically: if it's open, send free-form; if it's closed, fall back to a pre-approved utility or marketing template you've mapped for that scenario. Test the whole path with your own number first — send yourself an inbound, reply free-form, let the window lapse, and confirm the template fires correctly. Once live, watch delivery and read status, template approval status, and your quality rating. InfiQ shows delivered-message counts by category so you can see exactly where template spend is going and trim any templates being sent where a free reply would have worked.
- Map an approved template to each out-of-window scenario
- Test end-to-end with your own number before going live
- Monitor delivery/read status, quality rating and per-category counts
- Review category spend regularly to catch avoidable template sends
Frequently asked questions
When does the 24-hour window open and reset?+
Is the 24-hour window a billing unit? Do I pay per conversation?+
What can I send inside the open window?+
What happens if I try to reply after the window has closed?+
Which template category should I use to re-open a conversation?+
Does InfiQ track the window for me automatically?+
Do I need a developer to handle the 24-hour window?+
Can I send a template while the window is still open?+
Stop losing messages to a closed window
Let InfiQ track every contact's 24-hour window and switch between free-form replies and approved templates automatically — talk to our India-based team to set it up.