Chapter 14 of 15

How much a DIY AI agent costs

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 monthly bill and what breaks later.

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CertuAI free manual · Updated September 23, 2026 · Written by Bernardo Villela, CEO of CertuAI · see the whole manual

Summary in 5 facts

Short answer Only answering people who contact you, the bill starts near zero: cents of AI per conversation and free hosting.
The real cost is your maintenance time, which never ends.
Starting a conversation is charged per message by Meta.
Meta's key is revoked and sending stops with error 190.
The API version or the AI model is retired.

By the numbers

Number	What it means
US$ 75 per month	And where CertuAI comes in CertuAI costs from US$ 75 per month, for those who prefer to pay rather than maintain it.

How much does it cost to maintain an AI agent on WhatsApp?

Short answer

Only answering people who contact you, the bill starts near zero: cents of AI per conversation and free hosting. The real cost is your maintenance time, which never ends.

The bill

With a thousand conversations per month: API R$ 0, hosting R$ 0 at the start, AI around R$ 10. Starting a conversation is charged per message by Meta. Check the official table.

What holds down the AI bill?

Two lines in the chapter 11 file: how many exchanges go along with each call and the maximum length of the reply.

src/index.jsjavascript

const MAX_TROCAS = 10;                 // 10 do cliente + 10 do atendente

// dentro de pensarResposta, na parte 4:
generationConfig: { temperature: 0.4, maxOutputTokens: 300 },

What breaks?

Meta's key is revoked and sending stops with error 190.
The API version or the AI model is retired.
You change a price and forget to change the text.

Where people get burned

Send one test message a day to your own number. Otherwise the one who finds the outage is a customer.

Is it worth doing it yourself?

Worth it if you code and enjoy maintaining. Not worth it if your time is already in the operation.

Frequently asked question

Can I start on my own and migrate later?

You can. The business text and the rules go with you.

And where CertuAI comes in

CertuAI costs from US$ 75 per month, for those who prefer to pay rather than maintain it.

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In short

The open bill of an AI agent on WhatsApp that you build yourself, plus the list of what breaks over time: key, API version and price.