What is a WhatsApp bot?

How a WhatsApp bot works under the hood

A WhatsApp bot connects to a WhatsApp Business account through the WhatsApp Business API (the professional version, not the mobile app). Every incoming message reaches the bot service, which decides what to reply and sends the reply back. The API supports text, lists, buttons, images, documents and pre-approved message templates to start conversations.

There are two common architectures: menu-based bot (rule-based) and AI bot (based on language models). The first replies with a fixed tree of questions and answers: "1) book, 2) cancel, 3) talk to a human". It works but users hate it when the tree gets complex. The second understands natural language ("hi, I want to move my Thursday cut to a later time") and reasons over the schedule. The AI bot is more expensive to operate but the conversion to booking is notably higher.

Menu bot vs AI bot

The menu bot has a fixed script. It works if your cases are simple and predictable ("I want to book", "I want to cancel"). It fails when the client writes something that does not fit the menu ("hey, my cousin wants to come with me on Saturday") because it cannot interpret intent. The user ends up saying "human" and the automation promise breaks.

The AI bot uses a language model (GPT-4 or equivalent) that understands intent even when the client writes with typos, in plural or with irrelevant details. Marai’s bot is trained specifically for bookings: when a client says "I wanted a cut and wash on Friday at 6", the bot extracts service (cut+wash), day (Friday) and preferred time (18:00), checks real availability in your schedule and proposes the closest slot if that time is taken. And all in natural Spanish — not robotic questions.

What it solves for an appointment business

Four concrete problems. First, missed calls: while you are serving a client, the bot answers others and books without you stopping. Second, out-of-hours messages: the client writes at 10 p.m. and by 10.01 p.m. they have their Saturday appointment confirmed, without you having to check WhatsApp tomorrow. Third, hesitating clients: the bot replies with prices, service duration and real-time availability, which removes friction. Fourth, change management: cancelling or moving an appointment is a 30-second bot conversation instead of a 3-minute call.

The real outcome, measured in clients running the system for months, is 20-40 % more out-of-hours bookings captured and 1-3 hours per week off the phone. These are not marketing numbers: they are the mechanical consequence of having a channel open 24/7 that was closed before.

Real limitations worth knowing

A good bot does NOT replace the human receptionist for delicate cases (a serious complaint, a medical emergency, a price negotiation). What it does well is dispatch the 80 % of routine messages so the human can focus on the 20 % that really needs attention. Marai detects when a message is not a booking (e.g. a complaint or a complex question) and hands it to the human without losing context.

Another limitation: WhatsApp has strict rules about when you can start a conversation. To send a reminder or a confirmation you must use templates pre-approved by Meta or be within the 24-hour "service window" after a client message. This is good (prevents spam) but you have to understand it when designing automations.