AI agent for WhatsApp

The 24-hour window and what it costs

When the customer writes, a 24-hour window opens in which the agent replies freely and at no cost. Outside that window, only approved templates can be sent.

Since July 1, 2025, Meta charges per delivered template, with a price based on the category (marketing, utility or authentication) and the recipient's country. Utility templates sent within an open window are free (Meta pricing).

situation                                     what is sent            cost
customer wrote less than 24 h ago             any message             free
arrived from a click-to-WhatsApp ad (72 h)    any message             free
appointment reminder, outside the window      utility template        per message
follow-up with an offer, outside the window   marketing template      per message

Recommendation. Make sure the important things happen inside the open window: the quote, the payment link and the confirmation go in the same conversation in which the person asked.

A reminder template

The template is approved once and sent with variables. Replies to its buttons come back to the agent as just another message.

POST /{version}/{phone-number-id}/messages
{
  "messaging_product": "whatsapp",
  "to": "529981234567",
  "type": "template",
  "template": {
    "name": "recordatorio_reserva",
    "language": { "code": "es_MX" },
    "components": [{
      "type": "body",
      "parameters": [
        { "type": "text", "text": "Martina" },
        { "type": "text", "text": "Saturday, November 14" },
        { "type": "text", "text": "21:30" }
      ]
    }]
  }
}

Recommendation. One template per purpose, with text that makes sense even if the person doesn't remember the conversation. If a utility template mixes in promotion, Meta classifies it as marketing.

Buttons inside the conversation

Within the window, the agent can send interactive messages. Each button's identifier comes back unchanged, so there is no text to interpret.

{
  "messaging_product": "whatsapp",
  "to": "529981234567",
  "type": "interactive",
  "interactive": {
    "type": "button",
    "body": { "text": "There are two suites open for Friday. Which do you prefer?" },
    "action": { "buttons": [
      { "type": "reply", "reply": { "id": "suite_mar", "title": "Ocean view" } },
      { "type": "reply", "reply": { "id": "suite_jardin", "title": "Garden view" } }
    ] }
  }
}

Recommendation. Buttons for closed decisions and free text for everything else. An agent that only offers buttons turns into a phone menu.

What WhatsApp's policy allows

Since January 15, 2026, the WhatsApp Business terms prohibit offering general-purpose AI assistants through the platform (TechCrunch). An agent limited to your business, one that serves customers, books, collects payment or recommends products from your catalog, is allowed.

Recommendation. Keep the agent on business topics and hand off anything outside them.