Last updated:
09.03.2026
Session message (24-hour rule)
A session message is a WhatsApp message sent within a 24-hour window after the last customer message. Within this timeframe, companies can send freely worded messages without a pre-approved template – the so-called Customer Care Window.
hellomateo manages session windows automatically: As soon as a customer writes, the window opens, and employees and the AI assistant can respond freely and immediately.
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The 24-hour rule (also: Customer Care Window) is a key rule of the WhatsApp Business API: When a customer replies to a message or writes to the business, a 24-hour window opens. During this time, the business can respond with free, unapproved messages.
How does the session window work?
As soon as a user sends a message to a business, a 24-hour session begins. Within this time, agents or AI systems can communicate freely – without being required to use a template. If the business does not respond within 24 hours or wants to proactively contact the customer after this period, a message template approved by Meta must be used.
Session message vs. template message
Session messages are flexible and can be freely formulated – ideal for customer dialogues, support, and personalized advice. Template messages are necessary when the session window has expired or when proactive marketing messages are to be sent. Session Management with hellomateo: hellomateo automatically shows employees whether an active session window exists. If the window expires, the platform automatically switches to template usage – seamlessly and without manual intervention. This prevents messages from being accidentally sent outside the rules. Conversation Costs with Meta: Meta charges per conversation – not per message. A conversation includes all messages within a 24-hour window. hellomateo gives companies full transparency regarding incurred costs.