WhatsApp Business API: 24H window and message templates
Elsa Paparone
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Introduction
The WhatsApp Business API is today an essential channel for customer relations and transactional communication.
But its use is based on a strict framework defined by Meta: the 24-hour messaging window and message templates.
In this article, we explain :
- What the 24-hour messaging window is and how it works.
- When to use message templates.
- What's new in 2024-2025 (pricing, message categories, MM Lite API)
- Good compliance practices (opt-in, RGPD, unsubscribe).
- Concrete examples (JSON, workflows).
WhatsApp Business: how to use
WhatsApp Business is an accessible tool that can help you set up optimized customer journey scenarios, enabling you to offer your customers a fluid, natural experience. There are two ways to communicate with your customers via WhatsApp Business.
The first method takes you through the 24-hour customer service window. What's special about this is that it's available 24 hours a day, as soon as the customer starts a conversation with you.
The second method is the Template or HSM - Highly Structured Messages, initiated by the company.
This formula is only available to op-in customers (i.e. those who have already opted in to receive your content).
Customer Window
Template
Initiative
Initiative
Your customer
You
Content
Content
- session messages
- Templates
Templates
Opt-in
Opt-in
No, since it was your client who initiated the exchange himself...
Yes, since you're the one who's going to be in contact with your client
The 24-hour messaging window rule
When a user sends a message to a company, a 24-hour window automatically opens. During this period, the company is free to respond, with no restrictions on message content or format (text, image, video, document).
Each new message from the customer resets the 24-hour window.
👉 Official documentation: Meta Business Docs - Conversation windows
What happens when the 24-hour time limit has elapsed?
24 hours after your customer's last message, the dialog window closes automatically. You will then only be able to send messages in the form of Templates, which are sent on the company's own initiative.
Please note, however, that you must have your recipient's explicit consent for this type of sending. These templates are pre-validated by WhatsApp© . You can create them yourself and then submit them, or use the templates we provide.
This is particularly useful when your departments need more than 24 hours to resolve a problem. Following a Template message, you can reopen a Customer Messaging Window, simply by asking for a reply to continue the process. If the customer replies, the window reopens automatically!
Message templates: sending out of window
Once the 24-hour window has closed, the company can only write to the user using message templates pre-approved by Meta. These templates are essential for :
- Calling up a customer after 24 hours
- Send a transactional notification
- Distribute a marketing campaign
Official Meta template categories
- Utility: confirmations, shipments, appointment reminders.
- Authentication: OTP, verification codes.
- Marketing: offers, promotions, personalized recommendations.
👉 Documentation : Message templates - Cloud API
Pricing and developments 2024-2025
Since 2023, Meta has been charging for WhatsApp conversations by category rather than by message.
- Service conversations : initiated by the customer, within the 24-hour window.
- Utility conversations: transactional messages sent outside the window.
- Authentication conversations: identity verification, OTP.
- Marketing conversations: campaigns and promotional messages.
What's new in 2025
- Utility templates sent within the 24-hour window are free of charge.
- Meta introduces the Marketing Messages Lite API (MM Lite API), for sending limited-volume marketing campaigns, with a pacing mechanism to avoid spam.
- Pricing is therefore linked to the type of conversation opened and the user's region.
👉 Documentation : Pricing & conversation categories
Best practices & compliance
Mandatory opt-in
Examples of collection points: website, forms, in-store QR codes, SMS.
Authorized content
-
Authorized: useful information, confirmations, customer service, promotions with consent.
-
Prohibited: spam, misleading content, sensitive data (health, finance), unsolicited surveys.
Unsubscribe management
Always provide a clear way to unsubscribe ("Reply STOP to unsubscribe"), in compliance with the RGPD.
Practical examples of WhatsApp messages
Example of a JSON template (Utility - order confirmation)
{
"name": "order_confirmation",
"language": "fr",
"components": [
{
"type": "BODY",
"text": "Bonjour {{1}}, votre commande n°{{2}} a été expédiée. Livraison prévue le {{3}}."
}
]
}
Typical conversation workflow
[Client envoie un message] → Ouverture de la fenêtre de 24 h → Réponse libre possible
↓
[Fin de la fenêtre] → Envoi d’un template validé (ex. suivi d’expédition)
↓
[Client répond] → Réouverture de la fenêtre de 24 h
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