What is WhatsApp Business API?
Also called WhatsApp Business Platform, WhatsApp Cloud API.
The WhatsApp Business API is the programmatic interface Meta provides so businesses can send and receive WhatsApp messages at scale. Inbound messages reach the business as webhook events, and replies are sent through API calls from a verified business account with a registered phone number. It is distinct from the consumer app and from the standalone WhatsApp Business app.
Access runs through a business account that Meta verifies, a phone number registered to it, and either a hosted platform endpoint or a business solution provider. Inbound messages, delivery states, and read receipts arrive as webhook events. The API supports text, media, documents, location, and structured interactive messages such as reply buttons and list pickers.
The distinctive constraint is the messaging window. Once a person messages the business, the business can reply in free form for a defined period. Outside that window, contact must use message templates approved in advance by the platform, which limits unsolicited outbound and is metered separately from free form replies. Template approval and category are the mechanism governing proactive messaging.
In practice this makes the channel strong for conversations the customer starts and awkward for campaigns the business starts. Opt in has to be collected somewhere the customer can see it, and quality signals such as blocks and reports affect how much a number is permitted to send. The business profile carries a display name and verification state that customers use to judge legitimacy.
Because platform policies and limits are revised regularly, treat any specific figure you read as provisional and check the current platform documentation before designing around it. The stable parts are the mechanism: verified account, registered number, webhooks inbound, free form replies inside a customer initiated window, and approved templates outside it.
Key points
- Meta's programmatic channel, separate from the consumer and small business apps
- Inbound messages and delivery states arrive as webhook events
- A customer initiated window allows free form replies for a period
- Proactive contact outside that window requires approved templates
- Blocks and reports affect a number's sending quality state
In practice
A travel agency prints a WhatsApp number on its booking confirmation. A traveler messages to ask whether the airport transfer includes a child seat. The agent replies in free form inside the open window, confirms the seat, and updates the booking. Three weeks later, when a flight time changes, the agency can no longer simply message, so it sends a pre approved update template that reopens the conversation.