WhatsApp 24-Hour Window: What You Can Send, and When

A customer asks about a price on Friday evening. Your team writes a friendly reply on Monday morning, the API rejects it with error 131047, and nobody knows why. Or finance notices that replies, which everyone thought were free, now show up on the October invoice.

Both come down to the WhatsApp 24 hour window, which Meta calls the customer service window. It decides whether you may send a free-form message at all, and since October 1, 2026 it no longer decides whether that message is free.

This guide covers what opens and resets the window, what you can send inside and outside it, what it costs now, how the free entry point stretches it, and how to build your inbox and code around it. It applies to Meta's official WhatsApp Business Platform; the complete guide to the WhatsApp API covers the wider picture.

How the window works

The window opens when a user messages or calls your business number, and lasts 24 hours from their most recent message or call. Per Meta's documentation, each new message or call from the user resets the timer to a full 24 hours. Your own messages do not extend it.

A typical day with a furniture store's customer:

The window is tied to one of your business numbers and one user. Error 131047, which you get for a free-form message sent too late, says exactly that: more than 24 hours have passed since the recipient last replied to the sender number. If you run several numbers, a customer's window on one does not open a window on another.

Two caveats from Meta's docs. You still need the user's opt-in to message them at all. And Meta lists a known issue where, in rare cases, you receive a message but cannot reply within the window.

What you can send inside and outside the window

Inside the window you can send anything the Cloud API supports. Outside it, only approved templates.

Templates work in both states, which is why they are the safe default for anything automated. A shipping alert from your order system should always be a template, because you rarely know whether the customer wrote in the last day. Free-form messages are for people answering people.

Outside the window you also cannot "ping" a customer with a short free-form check-in. That has to be a template too, usually a utility template if it relates to their open request, or a marketing template if it does not. Our guide to WhatsApp message templates covers approval.

What it costs inside the window since October 1, 2026

The window used to double as a free zone. That is now only partly true. As of October 2026, per Meta's pricing page:

• Messages from the user are always free.
• Service messages, meaning your free-form replies, are free for the first 1,000 per business number per month. From the 1,001st, each is charged at the service rate for the user's country. The allowance does not roll over and resets at midnight in your Messaging account's time zone.
• Utility templates sent inside an open window were free from July 1, 2025 and are charged at the utility rate from October 1, 2026. Meta changed their pricing type in status webhooks from free_customer_service to regular.
• Marketing and authentication templates are charged at their category rate wherever you send them.
• Meta Business Agent messages are charged per token.

Two special cases. If a Messaging account has no payment method, Meta delivers service messages within the free tier and stops after it. And eligible government bodies and non-profits keep free service messages beyond the tier through December 31, 2027.

The window still matters for marketing. Meta's per-user marketing limit, which can block marketing templates with error 131049, does not count marketing messages sent inside a window the user opened by replying. Our explainer on service message charges walks through the new bill.

The free entry point: a longer, cheaper window

The free entry point is the one place where the window gets more generous. It starts when a user messages you from a Click-to-WhatsApp ad on the Android or iOS app; WhatsApp on desktop and web does not qualify.

1. The user's message opens a normal customer service window.
2. If you reply within that window, your reply is free and opens a free entry point window from the moment you replied.
3. The free entry point window can stay open for up to 7 days, per Meta's pricing page as of October 2026.
4. While it is open, Meta does not charge for marketing, utility, authentication or service messages. Meta Business Agent messages are still charged.

The free entry point changes what you pay, not what you may send. After 24 hours without a message from the user, the customer service window has closed, so you still need a template. The difference is that the template is free until the free entry point window ends. Like the customer service window, it is tracked per business and user, and it is shared by every Messaging account sending on that number. Our guide to the WhatsApp free entry point covers measurement and ad set-up.

Building around the window

Treat the window as data your system tracks, not something agents remember. Store the timestamp of each contact's last inbound message per business number, taken from the webhook's timestamp field rather than your server clock, and decide the message type at send time:

const WINDOW_MS = 24 * 60 * 60 * 1000;
const SAFETY_MS = 5 * 60 * 1000; // stop free-form sends 5 minutes early

function windowOpen(contact, now = Date.now()) {
  if (!contact.lastInboundAt) return false;
  return now - contact.lastInboundAt < WINDOW_MS - SAFETY_MS;
}

function buildMessage(contact, text) {
  if (windowOpen(contact)) {
    return { messaging_product: "whatsapp", to: contact.phone, type: "text", text: { body: text } };
  }
  return {
    messaging_product: "whatsapp",
    to: contact.phone,
    type: "template",
    template: {
      name: "enquiry_update",
      language: { code: "en" },
      components: [{ type: "body", parameters: [{ type: "text", text: contact.firstName }] }],
    },
  };
}

If a free-form send still fails with 131047, fall back to the template rather than retrying. Habits that help teams on the official API:

• Answer well inside 24 hours, including weekends. A Saturday enquiry answered on Monday morning has already lost the window.
• Show agents a countdown next to each chat, so they know when a reply will need a template.
• Keep a small set of approved utility templates for follow-ups such as "Your quote is ready" or "We have an update on your request", so a closed window never stalls service.
• End with a genuine question when one is needed. A customer's answer reopens the window naturally.
• Do not disguise marketing as utility. Meta reviews categories and can recategorize templates, which changes the price and can hurt quality.

If you want to skip templates entirely, see the trade-offs in WhatsApp API without templates.

Where Tenashi fits

The 24-hour window is a rule of Meta's official platform. Teams that mostly answer customers who already message them often hit it for the wrong reason: a reply that is a few hours late suddenly needs an approved template. Tenashi runs on your existing WhatsApp or WhatsApp Business number as a linked device, the way WhatsApp Web does, so there is no customer service window, no templates and no per-message fees. Your team can reply to Friday's enquiry on Monday from a shared inbox, with follow-up reminders and scheduled sends so it does not get forgotten.

The limits are different rather than absent. Tenashi is not Meta's API, so WhatsApp's normal anti-spam enforcement still applies to your number. Through the API, each number can start 50 new chats a day with people who never wrote to you, sends are paced several seconds apart, and identical text to many chats is paused. Plans start from $18/mo.

Read the API docs · Get started

FAQ

What is the WhatsApp 24-hour window?

It is the customer service window on Meta's WhatsApp Business Platform: a 24-hour period that opens when a user messages or calls your business number and resets with each new message or call from them. While it is open, you can send free-form messages. Once it closes, you can only send approved template messages.

Do my own messages reset the 24-hour window?

No. Only messages or calls from the user open or reset the window. Sending them more messages, even several in a row, does not extend it. The window closes 24 hours after the user's last message, so if they stop replying, you need a template for anything you send after that point.

Can I send a template inside the 24-hour window?

Yes. Templates can be sent at any time, inside or outside the window. Inside the window they are billed at their own category rate: marketing, utility or authentication. Since October 1, 2026, utility templates sent inside an open window are charged, whereas from July 2025 to September 2026 they were free.

Are replies inside the 24-hour window still free?

Partly. Since October 1, 2026, each business number gets 1,000 free service messages a month, and replies after that are charged at the service rate for the user's country. Messages inside a free entry point window from a Click-to-WhatsApp ad stay free. Eligible governments and non-profits keep free service messages through 2027.

Does the 24-hour rule apply to the WhatsApp Business app?

No. The customer service window is a rule of Meta's API platform. On the WhatsApp Business app, and on tools that link an existing account as a device, you can message contacts at any time. WhatsApp still enforces its anti-spam rules there, so messaging people who never asked to hear from you carries ban risk.

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Build the window into your data model and your team's habits, and it stops being a surprise. If your work is mostly replies on a number customers already use, see how Tenashi handles it.