⚡Quick answer -

When a customer responds to a WhatsApp template message, Meta immediately changes the conversation type — and this affects billing, messaging rules, and what you can send next.

When Customer responds to a Template message:

The following scenarios occur:

1. A 24-hour Service Window Opens Automatically

• When the user replies to any template message (Marketing / Utility / Authentication):
• A 24-hour user-initiated service window begins
• During this window, you can send:
• Free-form text
• Images
• PDFs
• Buttons
• Location
• ANY number of messages
• Even Utility templates for free
• No WhatsApp fees apply for messages sent inside this 24-hour window.
• Lasts for 24 hours from the customer’s most recent message

2. You Can Now Send Free-form Messages (No template required)

Once the service window opens:

• You can reply naturally without templates
• You do not need WhatsApp template approvals
• You can have a normal chat with the customer

3. Billing Status Changes Immediately

Before reply:

• You were in a Marketing / Utility / Authentication (paid) template context.

After reply:

• You switch to Service conversation
• All free-flow messages you send for the next 24 hours are free (including utility templates)

Even if the conversation started as a paid marketing template, once the customer replies → it becomes free.

4. Sending Additional Templates During This 24h Window

If you send a template message while the user-initiated 24h window is open:

• Utility templates → Free
• Marketing / Authentication templates → Paid (marketing & authentication is always billable unless in a free-service window)

So only marketing & authentication templates are chargeable, even inside the service window.

5. When the Customer Replies Again, the 24h Window Resets

Every customer message resets the timer.

Example:

• Customer replies at 10:00 AM → window open until tomorrow 10:00 AM
• Customer replies again at 8 PM → window resets until next day 8 PM

What Happens After 24 Hours Pass Without a User Message?

The service window closes.

Then:

• You CANNOT send free-form messages
• You can only message the customer by sending a template
• Templates become chargeable per-message again (marketing/utility/authentication)

Free-form messaging is disabled until the customer replies again

Important Notes

• Each new reply from the customer resets the 24-hour clock
• Only businesses can initiate with templates—customers can message anytime
• Your platform may show a lock icon or disable the reply field when the session closes