Rules that change. Meta regularly updates WhatsApp’s rules and prices. This guide describes the principles in force at the time of writing. For the amounts, always check Meta’s official page.
A customer messages you on WhatsApp at 21:00. The next day, three colleagues have read the message, nobody has replied, and the customer has gone elsewhere. With the WhatsApp Business app, everything happens on one phone. As soon as the team grows, messages get lost.
The WhatsApp Business API changes the way you work. It connects your number to a shared tool, or to an AI agent. One Meta rule then frames all your conversations. When a customer messages you, you have 24 hours to reply freely (see Meta’s rules).
This guide explains what the API changes compared with the app, what Meta charges and how to get it. You’ll also see what a WhatsApp AI agent does with it, and what stays with your team.
What is the WhatsApp Business API?
The WhatsApp Business API is the business access to WhatsApp provided by Meta. You’ll also see it called the “WhatsApp API” or the WhatsApp Business Platform: it’s the same thing. It isn’t installed on a phone. It connects your WhatsApp number to software.
Under Meta’s rules at the time of writing, it’s designed for businesses that want:
- several people on the same number, without passing a phone around;
- a tool that organises conversations, such as a shared inbox or a CRM;
- an AI agent that replies for them, following their instructions.
Your customer sees no difference. They message you on WhatsApp as usual, on the same number. Everything happens on your side: who reads the message, who replies, where the conversation is stored.
Remember one point from the start: the API has no screen of its own. To use it, you connect it to a tool. The tool displays the messages and shares them with the team. If you wish, it also lets an AI agent reply.
WhatsApp Business app or API: what’s the difference?
The WhatsApp Business app works very well for a sole trader who replies from their phone. The API meets a different need: sharing the number, organising conversations and automating some of the replies.
| WhatsApp Business app | WhatsApp Business API | |
|---|---|---|
| Where you reply | On the company phone | In a tool, from your computer |
| Who replies | Whoever has the phone in hand | Several team members, or an AI agent |
| The evening message | An away message, the same for everyone | An answer to the question asked, if an AI agent is connected |
| Writing first | By hand, one contact at a time | With a message template approved by Meta |
| Follow-up | In the phone’s history | Conversations organised and linked to your other tools |
| Cost | Free app | Messages charged by Meta according to their type, plus the price of the tool |
| What it asks of your team | Replying to every message | Choosing a tool, preparing your templates and instructions |
The right choice depends mostly on your volume and your team. If one person answers a few messages a day, the app is enough. If messages arrive in the evening, on several phones or in large numbers, the API will save you time, especially with a WhatsApp AI agent to answer them.
One last criterion matters: what you want to do after the conversation. Noting an appointment, updating a customer record, calling someone back: all of this needs a connected tool. With the app, these next steps stay manual.
What is the 24-hour rule on WhatsApp?
It’s the rule that governs all your conversations through the API. Under Meta’s rules at the time of writing, it works in two stages.
- The customer messages you: a 24-hour window opens. During that time, you reply freely, in your own words.
- You write first, or after those 24 hours: you use a message template approved by Meta. It’s a text prepared in advance, with fields to fill in, such as the first name or the date.
- Your customerThe customer messages youTheir message opens a 24-hour window.
- YouYou reply freelyFor those 24 hours, in your own words.
- After 24 hoursA template approved by MetaA text prepared in advance, with fields to fill in.
- Your customerThe customer replies to the templateA new 24-hour window opens.
Meta also sets a condition: to write first to a contact, you need their prior consent. So only import contacts into your tool who have agreed to be contacted on WhatsApp.
Here is how the rule applies to the most common situations:
| Situation | What you need | Example message |
|---|---|---|
| A customer asks a question | Nothing more: the window is open | A free-form reply, based on your information |
| Confirming an appointment booked by phone | An approved template | “Hello (first name), your appointment is confirmed for (date) at (time). Reply here to change it.” |
| Following up a quote with no reply | An approved template | “Hello (first name), have you had a chance to read the quote we sent on (date)? I can answer your questions here.” |
| Announcing an offer | An approved marketing template | “Hello (first name), (offer) until (date). Reply YES to find out more.” |
As soon as the customer replies to your template, a new 24-hour window opens. You can then carry on the conversation freely. So write templates that invite a reply: a simple question is enough.
A few simple rules help you write a good template:
- One request per message: confirm, follow up or announce, not all three at once.
- Clear fields to fill in: first name, date, time, quote number.
- Your business name in the first line, so the customer knows who is writing.
- An ending that invites a reply: a question, or a word to send back.
Prepare your templates once, for the situations that come up every week. Your team no longer rewrites the same text, and the tone stays the same from one message to the next.
How much does the WhatsApp Business API cost?
The cost has two parts: Meta’s fees, and the price of the tool you connect. Meta’s rates change regularly and differ from one country to another. Rather than copy a price list, here is the principle, to check on Meta’s official WhatsApp pricing page.
What Meta charges. Under its rules at the time of writing, Meta charges for certain messages. The price depends on two things:
- the message category: marketing (an offer, a promotion), utility (an update on an order or an appointment), authentication (a login code);
- the recipient’s country: the same message doesn’t cost the same everywhere, so check the rate for each country you write to.
What Meta doesn’t charge. Your free-form replies within the customer’s 24-hour window aren’t charged by Meta. A business that mostly answers incoming messages therefore sends few charged messages. One that often writes first, for offers or reminders, sends more.
What the tool costs. It comes on top of Meta’s fees. At Starleads, WhatsApp is included from Pro, at €239 excl. VAT a month with a 12-month commitment. Each conversation uses credits from the contact’s first reply. The fees Meta charges are not included in these credits: they stay separate.
To estimate your budget, sort your messages by type. How many replies to questions? How many appointment reminders? How many offers? With those three numbers, Meta’s price list becomes easy to read.
Take an agency that mostly receives questions in the evening. Its replies within the window opened by the customer aren’t charged by Meta. Its appointment reminders, sent the day before with a template, are charged according to their category. If it adds a monthly offer for its customers, those marketing messages add to the total.
How do you get the WhatsApp Business API, step by step?
Access goes through Meta, then through the tool you choose. Under Meta’s rules at the time of writing, here are the steps.
- Create or find your Meta business account (Business Manager). It’s the account that represents your business at Meta. It may already exist if you use other Meta services.
- Choose the phone number. It’s the one your customers will see. It can be a new number, or one already in use. Meta allows, under certain conditions, a number already used on the app to be moved to the API. Check the procedure in its documentation.
- Have your business verified, if needed. Depending on how you plan to use it, Meta may ask to verify your business. Keep your official company documents to hand.
- Connect the account to your tool. This is the step that gives the API a screen. Your conversations arrive in the tool, shared with the team.
- Prepare your first templates. Appointment reminder, quote follow-up: write them in advance. They then go through Meta’s approval.
With Starleads, step 4 happens in your workspace. You follow Meta’s sign-up steps, and your WhatsApp Business account is connected in a few minutes. The details are on our WhatsApp Business integration page.
Before you start, gather access to your Meta business account and the chosen number. Add the list of contacts who have given their consent. The rest is sorted out during the connection.
Three oversights often slow down the setup:
- the number still in use on a phone, without having read Meta’s procedure for moving it to the API;
- templates written at the last minute, when the first follow-up is already planned;
- contacts imported without their consent, who will have to be removed from the list.
What does an AI agent do with the WhatsApp Business API?
The API opens WhatsApp to an AI agent. Your customers get an answer at any hour, and your team finds every conversation organised the next morning. Your team can then focus on the cases that need an adviser.
With Starleads, Sara, your AI agent on WhatsApp, takes on this role, from Pro. Take a message received at 21:00: a customer asks which documents to bring to their appointment.
SaraGood evening! Please bring a form of ID and your signed quote. Would you like me to remind you of the address?21:04- Sara replies straight away, using your documents and her instructions. Opening hours, documents required, terms: she uses your information.
- She sorts the conversation. It arrives in your workspace with its transcript, a summary and a topic. Those that need an adviser stand out.
- She hands over when needed. Her instructions say what she does when she doesn’t know. She can note the request for your team. She can also offer a callback: Léa then calls the customer, thanks to workflows.
- She books the appointment. With your calendar connected, Sara offers a slot in the conversation.
- She follows up with a template. A quote still waiting for a reply? Sara messages the customer with your template approved by Meta, if they have given their consent.
In the morning, your team opens the sorted conversations. Those that need an adviser come first, with a summary of what the customer said. Nobody starts from scratch, and nobody asks the customer the same question twice.
You stay in control: the instructions, the documents, the templates and the moment a person takes over. Your opening hours change? You update the document, and Sara replies with the new version. On the Starleads side, conversations and their summaries are hosted by OVH in France, in the EU, and encrypted. They are never used to train the models.
To see Sara at work, visit our WhatsApp AI agent page.
In short
The WhatsApp Business API connects your number to a shared tool or to an AI agent. Its rule is simple: after a customer’s message, you reply freely for 24 hours. To write first, you use a template approved by Meta.
On budget, Meta charges for certain messages according to their category and the recipient’s country. Your replies within the window opened by the customer are not charged. Always check the amounts on its official page.
Your evening messages go unanswered? A WhatsApp AI agent answers your customers, and your team picks up the conversation the next morning.
