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WhatsApp Business API • Messaging Rules and Compliance • 3 min read

What is 24-hour rule in WhatsApp Business API?

Understand the 24-hour messaging window rule and how it affects your replies and template usage.

The 24-hour rule (service window) lets you send free-form replies only within 24 hours of a user’s last message. Outside the window, you must use an approved template to restart the conversation.

Key takeaways

  • Inside 24 hours: you can reply with session messages (no template required).
  • Outside 24 hours: you must send a template to reopen the conversation.
  • Marketing, utility, and authentication templates each start a billable conversation.

Related guides worth reading next

Strengthen this topic cluster by also reading WhatsApp Business API session window, Can we send message after 24 hours?.

When the window closes

  • You cannot send free-form messages after 24 hours.
  • To reach out, send an approved template (marketing, utility, or authentication).
  • A new conversation charge begins when you send that template.

Best practices

  • Set reminders before the window closes to ensure timely replies.
  • Use quick replies/bots to acknowledge users instantly.
  • Keep utility templates ready for follow-ups after the window.

FAQs

Can I send media in the session window?

Yes. Within 24 hours, you can send free-form text or media without a template.

Does the clock reset with each user message?

Yes. Each new user message restarts the 24-hour session window.

Can I send a marketing template after 24 hours?

Yes, any approved template type can reopen the conversation; the category sets the billing.

Explore more WhatsApp Business API resources

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What counts as valid opt-in, where to capture it, and how to document consent.

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Allowed/disallowed content, opt-in, opt-out, and template guidelines.

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