WhatsApp enforces a 24-hour customer service window to prevent spam and encourage quick support replies. The type of message you can send depends on whether this window is currently open or closed.

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When this matters

Understanding the customer service window is crucial when:
  • Designing automated chatbots or interactive support flows.
  • Sending transactional alerts, OTPs, or marketing notifications.
  • Handling agent-led customer service conversations.

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Key rules

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How the window works

When a customer sends a message to your WhatsApp Business number, it opens the customer service window.
  1. Active Session (Within 24 Hours): Your business can send free-form messages (session messages) to the user. Each time the user replies, the 24-hour timer resets.
  2. Expired Session (After 24 Hours): Once 24 hours have passed since the user’s last message, the window closes. You can no longer send free-form messages. To resume messaging, you must send an approved template message.
On unofficial channels, the 24-hour customer service window is not technically enforced by Meta, but adhering to it is highly recommended to protect your number from being blocked for spam.