What is the official WhatsApp API, and when do you need it?

If you have looked for a way to send order notifications or WhatsApp campaigns to your customers, or to have several staff answer from one number, you have probably come across "the official WhatsApp API". This article explains what it is, how it differs from the two WhatsApp apps, how its templates, fees and limits work, and when your store or business actually needs it, and when something else will do.

What is the official WhatsApp API?

"The WhatsApp API" is the common name for Meta's WhatsApp Business Platform, and specifically its hosted interface, the WhatsApp Cloud API. Meta describes it as an interface that lets you message and call on WhatsApp programmatically: instead of typing every message by hand in an app on a phone, your system or the platform you use sends it, automatically or from a dashboard your team works in.

Among the uses Meta lists: order confirmations and shipping updates, appointment reminders, product recommendations, one-time passcodes, and interactive experiences with buttons and lists.

The WhatsApp API is not an app you download. According to Meta, it needs a business portfolio, a WhatsApp Business account and a software application that connects to the interface. That is why Meta says working on it takes developer resources or a Business Messaging Partner that handles the connection for you, and describes the platform as suited to medium and enterprise businesses.

How is it different from WhatsApp and the WhatsApp Business app?

A business can use WhatsApp in one of three ways:

• The regular WhatsApp app: a personal messaging app, designed for communicating privately with friends, family and businesses. You can message customers from it one by one, but Meta itself says you and they will likely find it limiting.
• The WhatsApp Business app: a free app with everything the regular app has, plus tools for business: a business profile, a greeting message, an away message, quick replies, labels and a product catalog. It works on one phone number and links up to four devices alongside the phone.
• The official WhatsApp API: an interface rather than an app, which a platform such as ATMET Chat runs on: automatic messages on approved templates, campaigns to your customers, interactive messages with buttons and lists, and a team answering from one number.

The full comparison of the three, with what each can do and what each costs, is in our article on WhatsApp Business vs regular WhatsApp.

What are templates, and why does the WhatsApp API need them?

A template is a message you write once and Meta reviews before you use it, with variable slots that fill in for each customer, such as their name and order number. Meta says the review can take up to 24 hours.

Templates are the only type of message you can send to a customer outside the "customer service window". So every message you start yourself, such as an order confirmation, an appointment reminder or a campaign, needs an approved template.

Each template has one of three categories at Meta:

• Marketing: promotional messages, such as offers and campaigns.
• Utility: messages about a transaction or carrying information for the customer, such as an order confirmation or a shipping update.
• Authentication: identity verification codes.

Before you send any template, Meta requires the customer to have opted in to hearing from you. Ready-made templates for stores, with the rules that keep them from being rejected, are in our guide to WhatsApp message templates.

What is the customer service window?

When a customer messages you, a 24-hour window opens in which you can reply with any message, no template needed: text, an image or an interactive message. Every new message from the customer opens the window for another 24 hours.

Meta calls these replies "service messages": any message that isn't a template, whether a member of your team writes it or an AI from a third-party platform does. In ATMET Chat, AI replies to customers come with the Pro plan.

Once the window closes and the customer hasn't written again, only templates can reach them.

How much does the official WhatsApp API cost?

Meta charges per message delivered to the customer, at the rate of the customer's country, and doesn't charge for the messages customers send you. Two kinds of message are charged:

• Templates: by their category. Utility templates sent while the window is open have been charged since October 1, 2026, after a period when they were free.
• Replies (service messages): the first 1,000 replies each month are free from Meta for each number, and what's left doesn't roll over to the next month. Beyond them, replies are charged at the service message rate of the customer's country, since October 1, 2026.

If you haven't added a payment method to your WhatsApp Business account, Meta delivers only the first 1,000 replies of the month, and doesn't send templates at all.

You pay these fees to Meta directly, from the payment method on your WhatsApp Business account, and ATMET takes no margin on them. The rates for each country are on our Meta message pricing page.

How many customers can you message a day?

Meta limits how many different customers you can message outside the customer service window, that is with a template, in a moving 24 hours. The limit is set for your business portfolio and shared by all the numbers in it, and it goes up in steps: 250 customers, then 2,000, then 10,000, then 100,000, then unlimited.

To go from 250 to 2,000, Meta lists three ways:

1. Verify your business with Meta.
2. Have the partner you work with verify it.
3. Send 2,000 templates delivered to different customers within 30 days, at high quality.

Replies inside the customer service window don't count toward this limit, which covers messaging outside it. As for sending speed, Meta says it reaches up to 80 messages per second by default.

What happens to your number when you register it on the WhatsApp API?

Meta says a number registered on the interface can't be used with the regular WhatsApp app, and that a number in use on WhatsApp can't be registered until it is deleted from it first. The exception is a WhatsApp Business app number, which Meta connects to the API without a new registration. So what happens depends on where your number is today:

• If your number is on the WhatsApp Business app: the app keeps working on your phone after you connect. This is a feature of Meta's own, known as coexistence, and it belongs to no single provider: you reply from the app one chat at a time, the platform sends from the same number, and WhatsApp keeps the chat history in sync between them. What works in the app, what doesn't work through the API, and how to turn it on are in our article on coexistence.
• If your number isn't on the WhatsApp Business app: when you register it on the official connection, it moves there and stops working in the app.

When do you need the official WhatsApp API?

You need it when WhatsApp becomes a business channel rather than a personal chat. The main cases:

• You send customers messages you start yourself: an order confirmation, a shipping update, an appointment reminder or a campaign. All of these need templates, and templates are only sent through the interface. In ATMET Chat, campaigns go out only over the official connection, on Meta-approved templates.
• You message many customers: a campaign through the interface reaches the customers who agreed to hear from you, within the daily limit Meta sets.
• You want interactive messages: buttons and lists customers tap instead of typing, which come with the official connection.
• You want automatic replies around the clock: in ATMET Chat, from the Pro plan, the AI answers your customers from your store's data or from your business's files, and hands the chats that need a person to your team.
• More than one person works on the number: the WhatsApp Business app is built for one phone number, and Meta points businesses that need several users to the WhatsApp Business Platform. In ATMET Chat the shared inbox works on both connection methods: you add your staff to answer from the same number, and assign each chat to a person or a department.

When don't you need it?

If you have few chats and they are all replies to customers who message you first, the WhatsApp Business app may be enough: it is free to download, it has a greeting message, an away message, quick replies and a catalog, and Meta doesn't charge for what you send from it.

ATMET Chat also has a second method that doesn't go through the interface at all: ATMET Chat channels link your number as a linked device, like WhatsApp Web, so the app on your phone keeps working as usual. They are completely free, over ATMET Chat's servers, with no message fees from Meta, and they suit everyday replies, but they have limits on sending speed and don't support bulk campaigns.

So if your work is everyday replies only, ATMET Chat channels are enough. If you need campaigns or notifications on templates, you need the official connection.

How do you get started with the WhatsApp API through ATMET Chat?

ATMET is a Meta Business Partner, and the official connection (WhatsApp API) is included in every ATMET Chat plan: the plan price covers the platform subscription and the official connection, and you pay message fees to Meta directly, with no commission to ATMET.

The setup we recommend: start with the official connection (WhatsApp API), then add ATMET Chat channels, so the number works both ways at once. You connect your number from the WhatsApp page of the ATMET Chat dashboard.

• If you have a store on Salla, Zid or Shopify: ATMET Chat sends order notifications, abandoned cart reminders and campaigns to your store's customers, and on Salla and Zid review requests too. Details and plans are on the ATMET Chat page for stores.
• If your business has no online store: a restaurant, a clinic, a salon or an office gets a WhatsApp inbox for you and your staff, WhatsApp campaigns from an Excel or CSV file, and keyword auto-replies, and from the Pro plan the AI answers from your files. You can try all of it free for 14 days, with no credit card. Details are on the page for businesses.