About WhatsApp

What the WhatsApp Business Platform gives you, the rules that shape every message, and what to set up first.

WhatsApp reaches customers in the app they already use all day, in a thread they can reply to. Businesses send through Meta’s WhatsApp Business Platform, and OneXtel connects you to it — so the platform’s rules are Meta’s, and they shape how you plan every campaign.

The one rule that shapes everything

Meta separates messages into two kinds, and which one you can send depends entirely on when the customer last wrote to you.

	Template message	Session message
When you can send it	Any time	Only within 24 hours of the customer’s last message
Approval	Pre-approved by Meta before first use	None — write it freely
Typical use	You start the conversation: an order update, a reminder, an offer	You reply while a conversation is live

That 24-hour window is Meta’s customer service window. Once it closes, a free-form reply will not send, and you have to fall back to an approved template. Support teams feel this first.

Message categories

Every template is approved into a category, which decides what it may say and how it is priced.

Category	For
Marketing	Offers, launches, re-engagement
Utility	Updates about something the customer already did — orders, payments, bookings
Authentication	One-time passcodes

Getting the category wrong is the most common reason a template is rejected. A message that reads like an offer will not pass as utility, however it is labelled. See Template categories.

What you can send

Text, images, video, documents and location, with quick-reply buttons and call-to-action buttons that open a link or dial a number. Customers can reply, and their replies come back to you — which is the part that makes WhatsApp a conversation rather than a broadcast.

Before your first message

1. A WhatsApp Business Account and a number

   A number that is not already in use on the consumer WhatsApp app, with a display name Meta approves. See Onboarding WhatsApp.

2. Approved templates

   Anything that starts a conversation needs an approved template, so write these before you plan the campaign, not after. See Create templates.

3. Opt-in, and a way to opt out

   Meta requires customers to have agreed to hear from you, and to be able to stop. See Opt in and opt out.

Meta also applies quality ratings and messaging limits per number, based on how customers react to your messages. Blocks and reports lower your limit; useful, expected messages protect it.

Where to go next

Send your first campaign

Build and launch WhatsApp campaigns from the portal.

Get the channel switched on

What you supply, what you decide, what to have ready.

Send from your own code

The WhatsApp API — templates, sends, callbacks and error codes.

Send from your marketing platform

MoEngage, WebEngage and the other connectors.

Reference

• WhatsApp Business Platform — Meta’s own documentation for the platform underneath
• WhatsApp error codes — what each Meta rejection means