WhatsApp is where many customers already talk. Connecting an AI assistant to a business WhatsApp number lets people ask about prices, book appointments and get answers in an app they use every day, using the same knowledge as your website chat. The technical route is Meta's WhatsApp Cloud API. This guide explains what it is, what you need, how to set it up step by step with an assistant such as Crescelo, how the messaging rules work, what it costs and how to test before you announce it.
Meta's products, policies and prices change often. Use this guide for the shape of the process, and check Meta's current documentation for exact screens and fees.
What the WhatsApp Cloud API is
The WhatsApp Cloud API is Meta's hosted interface for businesses to send and receive WhatsApp messages by software. It replaces the older approach of running your own servers. A chatbot or assistant connects to it: when a customer sends a message to your business number, Meta forwards it to your assistant's webhook; the assistant replies through the API. It is different from the free WhatsApp Business app on a phone, which is for manual use by one person.
| WhatsApp Business app | WhatsApp Cloud API | |
|---|---|---|
| Who uses it | One person on a phone | Software and teams |
| Automation | Simple quick replies and away messages | Full assistants, integrations, templates |
| Setup | Install and verify a number | Meta developer app, business account, tokens and webhook |
| Best for | Very small businesses talking by hand | Businesses that want an assistant to answer and book |
What you need before you start
- A Meta Business account (Business Manager) for your company, ideally verified.
- A Meta developer app with the WhatsApp product enabled.
- A phone number for WhatsApp that is not already tied to a personal WhatsApp account; you can start with the test number Meta provides.
- A permanent access token created for your app through a system user, so it does not expire in a day.
- The phone number ID shown in the app's WhatsApp settings.
- An AI assistant with a knowledge base ready to answer questions.
If you run more than one brand, use a separate number and assistant for each.
Step-by-step setup with Crescelo
WhatsApp is included on Crescelo's Agency / Scale plan. You set up the Meta side yourself and connect it to your assistant.
- Create a Meta developer app. In Meta for Developers, create an app of the business type and add the WhatsApp product.
- Get your phone number ID and a permanent token. Note the phone number ID from the WhatsApp settings. Create a system user in Business Settings, give it access to the app and generate a permanent access token with messaging permissions.
- Enter them in Crescelo. Open Channels and Integrations, then WhatsApp. Enter the phone number ID and access token, and choose a verify token, which is a secret string you invent.
- Set the webhook in Meta. In the WhatsApp configuration of your Meta app, set the callback URL shown in Crescelo and the same verify token. Meta calls it to confirm ownership.
- Subscribe to message events. Subscribe the webhook to the messages field so incoming messages are delivered.
- Send a test message. Send a WhatsApp message to your number from your own phone and check that the assistant answers.
Keep the access token secret. In Crescelo it is stored encrypted, and you should never paste it into a public place.
How messaging rules work
WhatsApp limits how businesses can contact people, to protect users from spam.
| Situation | Rule of thumb |
|---|---|
| A customer messages you first | You can reply freely for a window after their last message (currently 24 hours) |
| You want to message after that window | You must use a pre-approved message template |
| You want to start a conversation | Only with a template and only to people who have opted in to hear from you |
| Marketing messages | Require opt-in and use templates; check Meta's category rules |
Because an assistant mainly replies to customers who message first, most of its conversations fall within the free reply window. Anything proactive, such as appointment reminders after the window closes, needs an approved template. Check Meta's current documentation for the exact windows and categories.
What it costs
Meta charges businesses for some kinds of messages, and the pricing model and rates have changed over time and differ by country and category. Replies to customers within the reply window have historically been free or cheap, while template messages such as reminders and marketing are charged. Check Meta's current pricing page for your region before you plan volumes. Separately, you pay your assistant platform and, with a bring-your-own-key product, your AI provider for the model usage. Crescelo's Agency plan is $399 a month and includes WhatsApp and Telegram; see pricing.
Designing a good WhatsApp experience
- Short messages. WhatsApp is fast and mobile. Keep replies concise, with line breaks.
- Same knowledge as your website. Customers should get the same answers in either place.
- Booking in the chat. Offer times and confirm. The confirmation can carry the address and change link.
- Clear handover. Make it easy to ask for a person and ensure someone will see it.
- Language. Customers on WhatsApp often write in their own language; test the ones you serve.
- Opt-in and opt-out. Respect requests to stop messages, and record consent for proactive messages.
The unified inbox matters if you use several channels; see unifying web, WhatsApp and Telegram in one inbox and website chat versus WhatsApp bots.
Testing before you announce the number
- Send a normal question and check the answer.
- Send a question your documents cannot answer and check it admits it.
- Send a booking request and confirm the booking is created and the confirmation arrives.
- Ask for a person and confirm your team is notified.
- Send an image or voice note and see how the assistant responds; decide what you want it to do.
- Test at a slow connection and from a second phone.
- Check that messages appear in your conversation history.
Privacy and compliance
WhatsApp conversations contain phone numbers and personal information. Tell customers they are talking to an AI assistant, link to your privacy policy, collect only what you need and keep the data only as long as necessary. Meta is involved in processing WhatsApp messages, so include it in your privacy documentation. If you serve people in Europe, read the GDPR checklist for chatbots. This is general information, not legal advice.
Vianmääritys
| Problem | Likely cause | Fix |
|---|---|---|
| Meta cannot verify the webhook | Verify token does not match, or the URL is wrong | Copy the callback URL and token from the assistant exactly |
| Messages do not arrive | Webhook not subscribed to messages | Subscribe to the messages field in the app configuration |
| The assistant replies to you but not to others | App is in development mode or number not live | Move the app to live mode and use a real business number |
| Token stops working | Temporary token expired | Create a permanent token with a system user |
| Replies fail after a day | Outside the reply window | Use an approved template for proactive messages |
| Duplicate replies | Webhook registered twice | Remove duplicate subscriptions |
Telegram as a simpler alternative
If your customers use Telegram, its bot setup is simpler: create a bot with BotFather, get a token and connect it. Crescelo supports Telegram on the same plan. See Telegram bot integration for business chat.
What customers actually message you about
On WhatsApp, messages tend to be short, quick and casual. Understanding the typical patterns helps you configure the assistant well.
| Message type | Example | What the assistant should do |
|---|---|---|
| Quick question | Are you open tomorrow? | Answer briefly from your hours |
| Price request | How much for a full service? | Give the price or range and offer to book |
| Booking request | Can I come in Thursday morning? | Offer real times and confirm |
| Change request | Need to move my appointment | Offer new times or the change link |
| Media | A photo of the problem | Acknowledge and pass to your team if the assistant cannot use it |
| Voice note | A spoken question | Say what it can handle and ask the customer to type, unless you have voice support |
Write your assistant's greeting for WhatsApp differently from your website greeting: shorter, friendlier and clear about what it can do. Include your business name so customers know they have the right number.
A rollout plan that avoids embarrassment
- Start with the Meta test number and a few internal testers.
- Connect your real number only when answers and bookings look right.
- Announce it quietly first, for example to existing customers who already message you.
- Add a WhatsApp link or button to your website, Google Business Profile and social pages once you are confident.
- Review conversations daily for the first two weeks and fix gaps.
- Add reminder templates for appointments after the core flow works.
Making WhatsApp the only way to reach you is risky. Keep other routes open, including the website chat and a phone number, until you have confidence in the setup.
Frequently asked questions
What is the WhatsApp Cloud API?
It is Meta's hosted interface that lets businesses send and receive WhatsApp messages using software, such as an AI assistant.
Can I connect an AI assistant to WhatsApp?
Yes. You create a Meta developer app, get a phone number ID and access token, and connect them to your assistant, which then answers incoming messages.
Does Crescelo support WhatsApp?
Yes, on the Agency / Scale plan, using the WhatsApp Cloud API with your own Meta credentials.
Is WhatsApp automation free?
Not entirely. Meta charges for some message types, and prices vary. Check Meta's current pricing. You also pay for your assistant platform and AI usage.
Can the assistant message customers first?
Only with approved templates and where customers have opted in. Replies to customers who message you are freer.
Can I use my existing WhatsApp number?
A number tied to the personal or Business app usually has to be migrated. Meta's documentation explains the options; using a new number is often simpler.
If you would like the same answers on WhatsApp as on your site, read about the messaging channels feature and start a free trial.
Further reading
- Google Search Central: creating helpful, people-first content: What Google looks for in useful pages.
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