WhatsApp Business API explained

A plain-language explanation of how the WhatsApp Business API works, key components, and compliance rules.

This explainer covers how the WhatsApp Business API is structured—numbers, templates, conversations, hosting, and delivery—so you know what happens between your software and a customer’s WhatsApp app.

Key takeaways

The API is accessed through a Business Solution Provider (BSP) or Meta-hosted option; you connect via HTTPS endpoints.

Conversations are billed by Meta based on type: marketing, utility, authentication, or service (user-initiated).

Outbound messages must use approved templates; free-form replies are allowed within 24 hours of the last customer message.

Components of the API stack

Your WhatsApp Business number connects to the API through a provider account. Messages flow through Meta’s servers and back to end users.

Key pieces:

Phone number connected to a WhatsApp Business account.
Verified Facebook Business Manager to own the number and profile.
Business Solution Provider (or Meta-hosted) handling infrastructure, webhooks, and template management.
Your application or automation platform that calls the API and renders inbound messages.

Conversation categories and billing

Meta bills per 24-hour conversation window, not per message. The category depends on how the conversation starts and what template type you use.

Categories you’ll see on invoices:

Marketing: campaigns and upsell messages.
Utility: transactional updates like orders, invoices, or reminders.
Authentication: one-time passcodes and login flows.
Service: user-initiated chats when customers message you first.

Templates and the 24-hour window

Outbound messages must use templates that Meta reviews. Within 24 hours of a user message, you can send session replies without templates. Outside that window, templates are mandatory.

Template best practices:

Keep placeholders clear (e.g., {{1}} for name, {{2}} for order ID).
Avoid spammy wording; focus on value and clarity.
Use sample values when submitting for approval.

Delivery, webhooks, and quality

Webhooks notify your system about message status changes and replies so you can update tickets, orders, or CRM records.

Meta tracks quality based on user feedback and blocks or throttles numbers with high block rates, so relevance and opt-in matter.

FAQs

Do I need to maintain servers to use the API?

No. Most businesses use a BSP or platform like BotMax AI that hosts the stack and provides the API connection, inbox, and compliance controls.

How long does template approval take?

Usually minutes to a few hours. If wording is unclear or promotional without consent, it can be rejected and must be revised.

Can I migrate numbers between providers?

Yes. You can port your WhatsApp Business number from one BSP to another while keeping history and reputation, following Meta’s migration steps.