What is the WhatsApp Business API?

The business number is connected to an account, and messages travel through a system instead of a phone app. That system can be a customer panel, a help desk or software the business builds itself. Incoming messages land there, and replies go out from the same place.

Setup goes through Meta's business verification. Company details are checked and the number is registered to the account. A number cannot run in the personal WhatsApp app and on the API at the same time, so a migrated number leaves the app.

The WhatsApp Business app runs on one phone. For a very small business it is enough, with quick replies, a catalogue and labels. But the number lives on that phone. When the person is away, messages wait; when they leave the company, the history goes with them.

On the API the number belongs to an account. Several people answer from it and everyone can see who wrote what. Notifications are sent by the system, conversations link to the customer record and the history stays with the business. In return, setup involves verification and template approval.

When a customer writes to a business, a twenty-four-hour window opens. Inside it the business can reply in free text. Once it closes, only templates approved in advance by Meta can be sent.

Templates are written during setup and submitted for approval, which usually takes a few days. Appointment reminders, order updates and payment notices go out as templates. A message that has not been approved cannot be sent.

The API starts to make sense when message volume outgrows one person's phone. Clinics and salons that run on appointments, restaurants taking orders, hotels handling reservations and offices managing enquiries are typical.

The second reason is institutional memory. Keeping the conversation with the business rather than an individual means the relationship survives staff changes. The third is measurement: response time, read rate and blocks appear on one screen.

On a connected line, an incoming message reaches the system first. A chatbot can look at it and answer from the business's own sources. When a question has no answer there, it does not invent one; it hands the conversation to a person with a summary.

The bot and the team share one number. For the customer there is a single line, and who answers changes behind the scenes. A handed-over conversation opens on the team's screen, so nobody asks the customer to repeat themselves.

The twenty-four-hour rule still applies. After the window closes the bot cannot send free text either, so reminders and updates are prepared as approved templates.

The first decision is the number. An existing one can be migrated, but it then leaves the personal app, which is why many businesses start with a separate line. The second is consent: marketing messages go only to people who opted in, and sending without consent can get the account restricted.

The third is channel health. If blocks and reports start to rise, sending should stop. Finally there is cost: Meta charges per conversation and the amount depends on country and message category, so check the current rate in Meta's own documentation. Under GDPR, note where the conversations are stored and for how long.