The WhatsApp 24-hour window is the period in which a business can reply freely to a customer through the official WhatsApp Business API, counted from that customer’s last message. Inside the window, any service message is allowed; outside it, the business can only send a template approved by Meta.
The rule comes from Meta’s service messages documentation and affects every conversation handled through the API. Since October 1, 2026, it also affects cost, because service replies are now charged per delivered message.
This guide explains how the window opens, renews, and closes, what can be sent at each moment, the free entry point window for ads, current pricing, three example timelines, a decision table, and the most common mistakes.
Key Takeaways
- The 24-hour window opens or renews with every customer message or call and, while it is open, allows any service message without prior approval.
- Once the window closes, the business can only reach the customer with an approved marketing, utility, or authentication template, always with opt-in.
- Since October 1, 2026, Meta charges for service messages (after 1,000 free per phone number each month) and for utility templates inside the window; only the free entry point window for ads removes delivery charges entirely.
What Is the WhatsApp 24-Hour Window?
The customer service window is the rule that separates conversations from campaigns on the official platform. It applies to anyone serving customers through the API, whether with human agents, an AI agent, or both on the same number.
How Meta’s Documentation Defines It
Meta calls this period the customer service window. When a user sends a message or calls the business, a 24-hour timer starts, and while it is running, the business can send any type of service message.
Service messages are free-form replies, written by an agent or generated by an AI agent. They do not need prior approval, unlike WhatsApp message templates, which go through Meta’s review before the first send.
Who Opens and Who Renews the Window
Only the customer opens the window. A message sent by the business, even an approved template, does not start the customer service period: it simply invites the person to reply, and their reply is what unlocks free-form conversation.
The window also renews. If the customer writes again before the period ends, the timer resets to 24 hours. The WhatsApp API glossary sums up this and other terms, such as template, category, and opt-in, in short entries.
How the Window Opens, Renews, and Closes
The window cycle has three moments: opening, renewal, and closing. Understanding each one avoids surprises, such as a reply blocked in the middle of a conversation or a follow-up that can only go out as a template.
Messages and Calls Restart the Timer
Calls count as well as messages. According to Meta’s calling pricing page, the window opens or renews when the customer calls the business, even if the call is not answered, and when they accept a call placed by the business.
In practice, the clock always counts from the customer’s last interaction, not from the business’s last reply. A long conversation can stay open for days, as long as the customer keeps writing before each 24-hour period runs out.
What Happens When Time Runs Out
When 24 hours pass with no new message from the customer, the window closes. From then on, a free-form reply sent through the API returns an error: Meta’s error code list describes code 131047 and tells you to use a template.
The documentation also records a known issue: in rare cases, the business receives the message but cannot reply within the window. That is why it pays to monitor send failures instead of assuming every reply was delivered.
What You Can Send Inside the WhatsApp 24-Hour Window
With the window open, the business has the most freedom the platform offers. It can reply with free-form text, media, and interactive messages, and it can also use templates when it wants a standard format, such as an order confirmation.
Service Messages and Accepted Types
Meta lists more than a dozen service message types accepted inside the window, all sent through the messaging API without prior review. The main groups are:
- Text and media: text, image, audio, video, and document, with or without a caption.
- Interactive: reply buttons, lists, link button, Flows, and location request.
- Contact and address: contact cards, location, and delivery address request.
These formats let you resolve the request in the conversation itself, with no template. Features such as WhatsApp Flows, which open forms inside the chat, help collect data with fewer messages back and forth and fewer typing errors.
Templates Can Also Go Out Inside the Window
Templates are not only for contacts outside the window. A business can send a utility template to confirm an order placed during the conversation, or an authentication template with an access code, even with the window open.
The difference is cost and category. Since October 1, 2026, utility templates sent inside the window are no longer free, and marketing templates have always been charged. The cost section below details what changed in each case.
What You Can Send Outside the Window
Outside the window, the rule is simple and strict. Meta’s official pricing page states that templates are the only type of message that can be sent outside the customer service window.
Approved Templates Only, With Opt-In
The template must have approved status. The templates documentation says review is automatic and can take up to 24 hours; while a template is in review or rejected, it cannot be sent through the API.
Consent is also required. Meta requires WhatsApp opt-in before any contact, with the business name clear to the person. Sending templates to people who did not agree violates the policy and weighs on the number’s quality rating.
Marketing, Utility, and Authentication
Meta’s template categorization defines three types. Marketing templates cover offers, news, and reactivation. Utility templates follow up on a customer action or request, with no promotional content. Authentication templates send verification codes.
A template that mixes a notice with a promotion is treated as marketing. A WhatsApp payment reminder, for example, only stays in the utility category if it carries no offer. The business is billed by the category applied at the time of each send.
Marketing also has its own limits. According to the marketing templates documentation, WhatsApp may limit how many marketing messages a person receives in a given period, and each user can stop receiving offers from a specific business.
Decision Table: What to Send in Each Situation
The table below is this guide’s quick reference. It matches the conversation situation with what the API allows you to send and the current billing rule, so agents and automations can decide without opening the documentation.
The Six Most Common Situations
Each row starts from a practical question the team asks. The cost column follows Meta’s page on non-template messages; rates by country are in the official price list, and the WhatsApp API cost calculator helps simulate a month.
| Conversation situation | What you can send | Delivery charge (since October 1, 2026) |
|---|---|---|
| Customer wrote less than 24 hours ago | Free-form service message or any template | Service charged per message after 1,000 free per phone number each month; template charged by category |
| Customer came from a Click-to-WhatsApp ad and the business already replied | Any message while both windows are open | Free during the free entry point window |
| Ad window open, but the customer service window closed | Approved template only | Free while the ad window is open |
| Customer’s last message more than 24 hours ago | Approved template only, to opted-in contacts | Charged by template category |
| Contact never wrote to the business | Approved template only, to opted-in contacts | Charged by template category |
| Customer asked not to receive messages | Nothing until they write again | No send |
How to Use the Table in Your Team’s Routine
The safest way to use the table is to turn it into a system rule, not something agents have to remember. The platform should show the window status and allow only the formats permitted at each moment of the conversation.
In the ConverZAP inbox, for example, the conversation shows the open window with its closing time. Once the period ends, only approved templates can be sent, and contacts who opted out are blocked.
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Test my agent for freeCreate a free accountThe Free Entry Point Window for Click-to-WhatsApp Ads
There is a second window, tied to where the contact came from. It applies to people who arrive through Click-to-WhatsApp ads, and it changes the cost of the conversation.
When the Ad Window Opens
Meta calls this period the free entry point window. It opens when the customer writes through one of these entry points using the app on Android or iOS, and the business replies within 24 hours with any type of message.
From that reply on, all messages are free of delivery charges, including templates, while the window is open, and it may remain open for up to 7 days, according to Meta’s pricing documentation. Messages sent from WhatsApp Web or the desktop app do not open this window.
Two Independent Windows
The ad window does not replace the customer service window. The documentation says the two are independent: if the 24-hour window closes, the business can again send only templates, which stay free as long as the ad window lasts.
That is why the first reply needs to be fast and useful. A WhatsApp landing page or a well-configured ad only takes advantage of the free window when someone, or an AI agent, is ready to reply in time.
How much will the WhatsApp API cost you?
ConverZAP’s free calculator uses Meta’s price table in Brazilian reais (BRL): enter how many marketing, utility, and service messages you send per month and see the estimated cost.
Calculate my costHow Much Each Message Costs Since October 1, 2026
Pricing changed on October 1, 2026, and the change hits exactly what happens inside the 24-hour window. The post on WhatsApp API pricing goes deeper into amounts; here the focus is on operations.
What Changed in Pricing
According to Meta, since October 1, 2026, service messages are charged per delivered message, which had not been the case since November 2024. Utility templates sent inside the window are also charged now, after being free since July 2025.
By market, the service rate is the same as the utility and authentication rates, with no volume discount tiers. The documentation also lists a free tier of 1,000 service messages delivered per phone number per month. Rates are in the official platform pricing table, and Meta Business Agent replies have their own per-token pricing.
Where to Check What Was Charged
The API itself reports what was charged. The message status webhook includes a pricing object with the billing type: regular means a charged message, and free_entry_point means a free message under the ad window.
With that data, the business can compare cost per conversation and per entry channel. Resolving a request in fewer messages now cuts cost, not just handling time. Businesses using the WhatsApp Cloud API receive these webhooks at their configured endpoint.
Three WhatsApp 24-Hour Window Timelines
The three timelines below are illustrative examples from a fictional business, Example Store. They show what can be sent at each point and where charges apply, under Meta’s rules in effect in October 2026.
The Customer Starts the Conversation
At 10 AM, a customer asks whether a size is available, and the window opens. At 10:05 AM, the agent replies with text and a photo; at 10:20 AM, they send the payment link. These are service messages, charged per delivery since October 1, 2026, once the number has used its 1,000 free messages for the month.
The next day at 11 AM, the customer has not written again, and the window closed at 10 AM. The notice that the order is out for delivery has to be an approved utility template, charged by category. If she replies, the window opens again.
The Business Starts With a Template
The store sends a marketing template to opted-in contacts announcing a new collection. This send is charged and does not open a window. A bulk messaging campaign follows the same rule, with one template per contact.
Two hours later, a customer replies asking the price of an item. Now the 24-hour window is open, and the agent or the AI agent can chat freely, with each service reply counted toward billing.
The Customer Arrives From an Ad
A customer taps an ad on Instagram and writes from their phone. The store replies within ten minutes: that reply is free and opens the ad window. While it stays open, replies and even templates go out with no delivery charge.
If the customer stops replying for more than 24 hours, the customer service window closes, but the ad window stays open. The store can send a free utility template with a summary of the quote, as long as it is within the official period.
Common Mistakes With the Customer Service Window
Most problems with the window are not technical but routine. They show up when the team treats the API like the regular app or when an automation was built without considering the customer service period.
Operational Mistakes
The most frequent operational mistakes happen when people or automations ignore the deadline. The three most common are:
- Replying late: a free-form message sent after the deadline fails and has to become a template.
- Free-form follow-up: a follow-up scheduled for the next day will not go out without an approved template.
- Blind automation: an n8n flow with the official API that ignores the deadline causes failures in bulk.
It is also common to confuse the window with automatic replies. WhatsApp Business automated messages are an app feature; on the API, a greeting or away message is a service message like any other, charged since October 1, 2026.
Category and Consent Mistakes
Another mistake is disguising a promotion as utility to cut costs. Meta reviews the categories of approved templates and can change them; according to the documentation, businesses that abuse the system lose the advance notice before the change.
The last mistake is treating a template as a license to message anyone. Without opt-in, it violates the WhatsApp Business Messaging Policy. Blocks and reports lower quality, Meta limits numbers with low quality, and the path can end in a blocked number.
How to Organize Customer Service Around the Deadline
The 24-hour window shapes the routine of anyone serving customers through the API. With per-message pricing, it also shapes the budget, and both are solved with process, tools, and templates approved in advance.
The Team’s and the AI Agent’s Routine
The first step is to sort the queue by waiting time, so no conversation closes without a reply. An AI agent or chatbot can give the first reply right away and hand the case to the team with a summary.
This human and AI customer service model works best with multiple agents on the same number. Keep approved utility templates for the most common follow-ups, such as quotes, orders, and appointments, plus one for customer reactivation for contacts who went quiet.
How ConverZAP Helps
ConverZAP uses the official WhatsApp API and shows in each conversation how much time is left before the window closes. The AI customer support agent replies within the deadline, and after it, the inbox only allows approved templates.
Templates are created and tracked in the same dashboard, and an unsubscribe blocks new sends until the contact writes again. To see the full flow, ConverZAP offers a free trial with the inbox, the agent, and templates.
Frequently Asked Questions
The questions below cover the most common doubts about the WhatsApp 24-hour window, based on Meta’s official documentation and the guides on the ConverZAP blog.
When the customer sends a message or calls the business, a 24-hour period for free-form replies through the official API opens. Each new customer message restarts the period. When it ends, only approved templates can be sent.
Outside the 24-hour window, the business can only use a template approved by Meta, in the marketing, utility, or authentication category, and only for contacts who opted in. If the customer replies to the template, the window opens again and the conversation is free-form once more.
Yes. According to Meta, the 24-hour window opens or renews when the customer calls the business, even if the call is not answered, and when they accept a call placed by the business through the Calling API.
Not anymore. Since October 1, 2026, Meta charges per delivered message for service replies, after 1,000 free per phone number each month, and for utility templates sent inside the window. The exception is the free entry point window, opened by Click-to-WhatsApp ads.
No. Only a customer message or call opens or renews the window. The template is charged by category and works as an invitation: free-form conversation only starts when the person replies.
The API returns error 131047, which means more than 24 hours have passed since the customer’s last message. The fix is to send an approved template and wait for a reply. Meta’s opt-in page is a reminder that the contact must have agreed to receive messages.
