The 24-Hour Messaging Window

WhatsApp's 24-hour customer service window - when you can send free-form messages, when you need a template, how Avox shows it in the Inbox, automations, Calls and the API, and how to reopen a conversation.

WhatsApp separates messages a customer asked for from messages a business starts on its own. The line between them is the customer service window: a 24-hour period that opens each time a customer messages you. This is Meta's rule for every business on the WhatsApp Business Platform, and Avox follows it everywhere you can send from - the Inbox, automations, Calls and the Avox API.

The rule#

• The 24 hours count from the customer's latest message. Every new message from them starts a fresh 24 hours.
• Your own replies don't extend the window - only the customer's messages do.
• When a template brings the customer back and they answer, a new window opens.
• The window belongs to one business number. A customer who wrote to one of your connected numbers has opened a window on that number only, not on your other numbers.

What opens the window, and what doesn't#

The window and Meta's pricing#

The window also shapes what Meta charges. Free-form replies inside the window carry no Meta charge. Template messages are charged per message by category, and Meta doesn't charge for Utility templates sent while a window is open. Rates and rules are Meta's and can change - see Pricing for how this shows in Avox.

How Avox shows it#

In the Inbox#

Avox works out the window from the time of the contact's latest incoming message to the number you're replying from.

• The chat header shows the time left, for example Reply window: 5h 12m left. It turns amber when less than two hours remain, and reads Reply window closed once the 24 hours are up. Hover it to see "You can reply freely for 24 hours after their last message".
• Window open - the composer reads "Write a message…" and you can reply.
• Window closed - a note above the composer reads "It's been over 24 hours since this contact last messaged you - send a template to reopen the conversation." The composer is disabled and reads "Composer disabled - 24-hour window closed". See AVX-3059.

Avox checks the window again on the server when you press send, so a message never goes out in a window that closed while the conversation was open. In the window's final minute, Avox already treats it as closed, so a reply can't reach WhatsApp just after the window ends.

In automations#

Automations reply to messages as they arrive, so their replies go out inside the window.

• Send a template ("One of your Meta-approved templates - works even outside the 24h window") is the one message action that still sends after the window has closed.
• Every other message action - text, media, buttons, lists, Flows, locations, contact cards, link buttons and Request a call - is skipped when the window has closed, and the automation carries on with its next step.
• Wait for reply and Delay steps end a little early when the window would otherwise close first, so the next message can still be sent.
• The No-reply follow-up trigger only follows up while the window is still open.

See Actions and Triggers.

On Calls#

A call permission request - from Request calling permission on Calls, Request a call in the Inbox header, or an automation's Request a call step - is a regular message, so it uses the same window. Outside it, Avox shows "It's been over 24 hours since this contact last messaged you - send a template to reopen the conversation." For those customers, send an approved template of the Calling permission request type instead. See Calling on WhatsApp.

In the Avox API#

The Avox API sends whatever you ask it to. Outside the window, Meta refuses free-form messages and the API returns the error code outside_messaging_window ("It's been more than 24 hours since this person last messaged you. Send an approved template instead.") - see API errors. Send a template message instead (see Message types). In Meta's own terms this is error 131047, "Re-engagement message" - see Meta error codes.

Reopening a conversation#

1. 1

   Get a template approved

   Create a template that suits the reason you're getting in touch - for example a Utility template for an order update. See Create, or start from Meta's pre-verified templates in the Library.

2. 2

   Send it

   Send it from an automation's Send a template action, through the Avox API, or from a tool connected to it such as n8n, Make or Zapier. The premade Re-engagement with a template automation does this for contacts another automation tags re_engage.

3. 3

   Wait for the reply

   When the customer replies, a new 24-hour window opens and the Inbox composer is available again.

Working well with the window#

Common questions#

Related#

Last updated 12 October 2026