The WhatsApp Business API, now formally called the WhatsApp Business Platform, is Meta’s system that lets a business send and receive WhatsApp messages through software such as a CRM, a helpdesk or a chatbot, rather than from one phone. It is built for teams that need several people or automations to handle conversations, send order updates or run marketing messages at volume.
How the WhatsApp Business API works
There are two separate products. The WhatsApp Business app is a free phone app for a sole trader or small shop answering messages by hand. The API has no app of its own: you connect it to other software, either directly through Meta’s Cloud API or, more commonly, through a business solution provider that adds an inbox, templates and reporting. At the time of writing (October 2026), the older self-hosted version has been retired, so new setups run on the Cloud API.
Several rules shape how it behaves:
- The 24-hour window. When a customer messages you, a customer service window opens. Within it, you can reply freely with any content.
- Message templates. To start a conversation, or to message someone outside that window, you must use a pre-approved template. Templates are categorised as marketing, utility (order and account updates) or authentication (one-time codes), and Meta reviews each one.
- Quality and limits. New numbers can only message a limited number of people a day. The cap rises as you send good-quality messages, and falls if recipients block or report you.
- Pricing. Meta charges for template messages, not for free-form replies inside the window, and marketing templates cost the most. The cost section of the FAQ below gives the detail.
Conversations often begin from click-to-WhatsApp ads on Facebook and Instagram, a WhatsApp button on your website, or a QR code in store.
Why it matters
WhatsApp is a channel many UK customers already check constantly, and a reply there can feel more personal than an email. For bookings, delivery updates, quotes and after-sales questions, it can shorten the gap between enquiry and answer. It also supports conversational commerce, where a customer asks questions and moves towards buying within the chat.
The rules are strict, and the UK has two layers of them. Meta’s own policy requires you to collect opt-in before messaging someone, stating your business name and what they will receive. Separately, PECR applies to electronic marketing messages, so marketing templates need consent, or the soft opt-in for existing customers who were given a clear chance to refuse. Service messages, such as an order update, are not marketing, but slipping a promotion into one changes that.
Common mistakes
- Uploading a contact list and broadcasting. Having someone’s mobile number is not consent to market to them on WhatsApp.
- Labelling promotions as utility templates. Meta reclassifies them, and recipients who feel spammed block you, which lowers your quality rating.
- No one answering replies. A broadcast that invites responses needs staff or a well-built automation behind it, within the hours you promise.
- A chatbot with no route to a person Leaving customers stuck in loops.
- Ignoring opt-outs. When someone says stop, the opt-out must reach your CRM and every other channel that uses their number.
How to act on it
Decide first whether you need the API at all. If one or two people answer messages, the free app may be enough. The API earns its place when you need a shared inbox, CRM integration, automated updates or marketing at volume.
If you go ahead, choose a provider, verify your business portfolio in Meta Business Suite, and register a number that is not already active on the consumer or business app. Build your opt-in into checkout, booking and enquiry forms with clear wording, and record when and how each person agreed. Draft utility templates first, since they carry the least risk, then add marketing once consent is in place. If WhatsApp conversations will come from ads, my click-to-WhatsApp and Messenger ads service covers the campaign side and how to measure what each chat is worth.