WhatsApp Business API Integration

Description

Integration WhatsApp Business API integration: templates, webhooks and opt-in

A WhatsApp Business API integration lets your own software send approved template messages (order updates, reminders, one-time passwords) and receive customer replies through Meta's Cloud API. The work is mostly in the rules around the API: opt-in, template approval, the 24-hour customer service window, messaging limits and signed webhooks. This guide follows Meta's documentation as read on 2 October 2026.

Discuss an integration Last updated 2 October 2026

What the integration does

The WhatsApp Business Platform is Meta's programmatic way to message customers on WhatsApp. Its Cloud API is hosted by Meta: your server calls it to send a message, and Meta calls your server (by webhook) when a customer replies or when a message is delivered or read.

An integration puts that inside your own software. An order that ships sends a tracking message. A missed payment sends a reminder. A reply from the customer appears in your CRM, or is answered by an assistant.

Three things are needed before a single message can be sent, according to Meta's overview: a business portfolio, a WhatsApp Business Account inside it, and a business phone number.

Data that flows each way

Event or object

Direction

What your system does with it

Opt-in

Customer to your system

Stores who agreed, when, where and to what kinds of message

Template (category, language, body with variables)

Your team to Meta, for review

Stores the template name and its status; sends only approved templates

Template message ( POST /{phone-number-id}/messages )

Your server to Meta

Stores the returned message id against the order or customer

Status: sent, delivered, read, failed

Meta to your server (webhook)

Updates the message log; on failure, falls back to SMS or email

Incoming message

Records it, opens the 24-hour window, routes it to a person, a bot or the CRM

Free-form reply

Sent only while the window is open

Opt-out ("stop")

Marks the customer as not to be messaged, in every sending path

The main flow, step by step

Set up the account. Create the business portfolio, the WhatsApp Business Account and the phone number. Verifying the business is one of the ways Meta lists to raise the starting messaging limit.

Collect opt-in. Meta requires opt-in before you message someone, stating clearly that the person agrees to receive messages from your business, by name.

Write and submit templates. Each is categorised as marketing, utility or authentication. Review is automatic and can take up to 24 hours.

Register the webhook. Meta first sends a verification request ( hub.mode , hub.challenge , hub.verify_token ) that your endpoint must answer. After that, each notification carries an X-Hub-Signature-256 header to check against your app secret.

Send on a business event. Your system calls the messages endpoint with the template name and its variables. A success response means Meta accepted the request, not that the message was delivered.

Follow the statuses. Delivery and read receipts arrive by webhook and are matched to the message id.

Handle the reply. A customer message starts a 24-hour customer service window. Inside it you may send free-form messages; once it closes, only templates.

Limits and rules Meta documents

Rule

What the documentation says

Customer service window

24 hours from the customer's last message or call; outside it, only approved templates can be sent

Template review

Automatic; can take up to 24 hours; a template can later be paused or disabled if its quality rating falls

Template count

250 per WhatsApp Business Account for an unverified portfolio; up to 6,000 for a verified one

Messaging limit

New business portfolios can message 250 unique users in a moving 24-hour period, outside service windows; the tiers above are 2,000, 10,000, 100,000 and unlimited

Shared limit

The limit is set for the portfolio and shared by all its phone numbers

Throughput

Up to 80 messages per second per business phone number by default

Pair rate

1 message every 6 seconds to the same user

Webhook endpoint

HTTPS with a valid certificate; self-signed certificates are not supported

Webhook retries

If your endpoint does not return HTTP 200, Meta retries with decreasing frequency for up to 7 days; retries can produce duplicates

Webhook payload

Up to 3 MB

Meta's documentation describes these limits as moving up automatically when message quality is good and volume is used, and moving templates to paused when recipients respond badly. Both are outside your control once messages are sent, which is why what you send matters more than how.

Common failure modes

Messages rejected outside the window. Code that replies with free text works in testing, when the tester has just messaged the number, and fails for real customers a day later. The system has to know whether a window is open and choose a template when it is not.

Launch blocked by the 250 limit. A new portfolio cannot message a whole customer list on day one. Verification and a staged roll-out need planning.

Wrong category, higher bill. Meta's template guidelines class mixed content, such as an order update with a promotion in it, as marketing, and Meta re-categorises approved templates that sit in the wrong category. Category decides price.

A paused template nobody noticed. The send call fails and order updates stop. Template status needs monitoring and an alert.

Duplicate handling. Retried webhooks create two CRM notes or two bot replies unless the message id is checked.

Opt-out honoured in one place only. The marketing tool respects "stop" and the order system does not. Opt-out has to sit in one record that every sender reads.

Assuming sent means delivered. The API response confirms acceptance only. Delivery is a later event.

Fees

As of October 2026, Meta's pricing page says:

You are charged when a template message is delivered. This per-message model replaced per-conversation pricing on 1 July 2025.

Marketing templates are always charged. Utility templates are free when delivered inside an open customer service window. Non-template messages inside the window are free.

When a customer arrives from a click-to-WhatsApp ad or a Page call-to-action button and you reply within 24 hours, a 72-hour free entry point window opens in which all messages are free.

Rates depend on the template category and the country calling code of the recipient. Volume tiers lower the rate for utility and authentication templates.

Meta lists a higher marketing rate for India from 1 January 2026.

The rupee figures sit in Meta's rate cards, linked from that page. They are not repeated here because they change: the page lists rate updates effective 1 July 2026 and 1 October 2026. Guides written before July 2025, which describe a charge per conversation, no longer match how billing works.

What WavX builds around it

For a client who needs WhatsApp connected to a store, app, CRM or internal system, WavX builds:

Sending tied to real events in your system: order placed, shipped, payment due, appointment tomorrow.

A message log per customer, with status, template, category and the event that triggered it.

Window tracking, so the system picks free-form or template correctly.

A verified, duplicate-safe webhook receiver for replies and statuses.

Opt-in capture at checkout or sign-up and a single opt-out record.

Routing of replies to your team, to your CRM (see WhatsApp and CRM integration) or to a WhatsApp AI chatbot with handoff to a person.

Alerts when a template is paused or a send fails, and a fallback channel.

Pricing is quoted after scoping. For planning, the software cost estimator carries third-party integrations as a ₹60,000 feature line on top of a base build; an AI assistant on WhatsApp is estimated separately in the AI cost calculator . Both give planning ranges, not quotes.

When you do not need the API

You want a chat button. A click-to-chat link ( https://wa.me/ followed by your number) opens a chat with you and can carry a pre-filled message. See how to add WhatsApp to a website .

One or two people answer every chat. The WhatsApp Business app is free to download and includes a catalogue, labels, and greeting and away messages.

You want broadcasts and a shared inbox, not a link to your own software. A ready-made tool from a WhatsApp solution provider covers that. How to send automated WhatsApp messages compares the routes.

The API through a custom integration is worth it when messages must be triggered by, and written back to, systems you already run.

Frequently asked questions

Do I need the API, or is a WhatsApp button on the website enough?

If you only want visitors to start a chat with you, a click-to-chat link is enough and needs no API. You need the API when your software has to send messages by itself, such as order updates or reminders, or when replies have to land in a CRM or be answered by a bot.

How is WhatsApp Business messaging priced?

Since 1 July 2025 Meta charges per delivered template message, with the rate set by the template's category and the country code of the recipient. Marketing templates are always charged; utility templates sent inside an open customer service window are free, as are free-form replies inside that window. The rupee rates are on Meta's rate card, which we do not reproduce because it changes.

How long does template approval take?

Meta's documentation says templates are reviewed automatically and that review can take up to 24 hours. A template that is rejected has to be edited and resubmitted, so templates should be written and submitted early in a project, not in the last week.

Can you send messages to customers who have not opted in?

No. Meta requires a business to obtain opt-in before messaging a person, and the opt-in has to make clear that the person is agreeing to receive messages from your named business on WhatsApp. We build the opt-in capture and store the record.

Can the same number be answered by people and by a bot?

Yes, that is a routing decision in your own software. Incoming messages arrive at one webhook, and your system decides whether a person, a rule or an AI assistant answers. We build the handoff so a customer can always reach a person.

Sources

Meta for Developers: WhatsApp Cloud API overview · read 2 October 2026

Meta for Developers: WhatsApp Business Platform pricing · read 2 October 2026

Meta for Developers: Messaging limits · read 2 October 2026

Meta for Developers: Message templates · read 2 October 2026

Meta for Developers: Send messages · read 2 October 2026

Meta for Developers: Set up WhatsApp webhooks · read 2 October 2026

Meta for Developers: Graph API webhooks, getting started · read 2 October 2026

Meta for Developers: Get opt-in for WhatsApp · read 2 October 2026

Meta for Developers: Template category guidelines · read 2 October 2026

WhatsApp Help Center: How to use click to chat · read 2 October 2026

WhatsApp Business: the WhatsApp Business app · read 2 October 2026

Related

WhatsApp AI chatbot

How to send automated WhatsApp messages

How to add WhatsApp to a website

What is a webhook?

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