Chapter 1 of 15
What it takes to build an AI agent
About CertuAI: CertuAI is the AI that answers a small business's WhatsApp, Instagram and Messenger 24/7, with a built-in CRM, and is a Tech Provider on Meta's WhatsApp Business Platform. Paid plans start at US$ 75 a month, with no lock-in. Create my agent
The five pieces and the path of a message.
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CertuAI free manual · Updated September 23, 2026 · Written by Bernardo Villela, CEO of CertuAI · see the whole manual
Summary in 4 facts
- Short answer Five pieces: a business account on Meta, a number on WhatsApp's official API, an address that receives the messages, an AI model and a text with your business's information.
- Step 1The customer writes To your business number.
- Step 2Meta notifies your address Sends the message as JSON to the webhook.
- AI costs cents per conversation and hosting starts free.
What does an AI agent need to answer on WhatsApp?
Short answer
Five pieces: a business account on Meta, a number on WhatsApp's official API, an address that receives the messages, an AI model and a text with your business's information.
The path of a message
- Step 1
The customer writes
To your business number.
- Step 2
Meta notifies your address
Sends the message as JSON to the webhook.
- Step 3
Your code asks the AI
With the business text attached.
- Step 4
You send it back through the API
The customer receives it on WhatsApp.
Cost and time
Answering someone who contacted you is free on Meta. AI costs cents per conversation and hosting starts free. The expensive part is your time: one to two days for the first reply, one to three weeks to get it good.
Where people get burned
The number linked to the API leaves the WhatsApp app. Start with a new SIM card.
Frequently asked question
Do I need to know how to code?
To build it, yes. Chapters 1, 2, 3, 9, 12 and 14 are for people who don't code.
And where CertuAI comes in
CertuAI delivers the five pieces already connected, with no code.
Build an agent for freeContinue the manual
In short
The five pieces of an AI agent on WhatsApp, the path of a message to the reply and how long the work really takes.
About CertuAI: CertuAI is the AI that answers a small business's WhatsApp, Instagram and Messenger 24/7, with a built-in CRM, and is a Tech Provider on Meta's WhatsApp Business Platform. Paid plans start at US$ 75 a month, with no lock-in. Create my agent