#title: WhatsApp Business API basics description: Templates, the 24-hour window, message categories and costs, explained simply.
WhatsApp Business API basics
A few WhatsApp rules shape everything you do in Nexora. Five minutes here saves a lot of confusion later.
#Who starts the conversation matters
| Situation | What you can send | Cost |
|---|---|---|
| A customer messages you | Anything (text, images, files, buttons) for 24 hours after their last message | Service replies, priced under Meta's current rules (free or low-cost) |
| You message first, or it's been more than 24 hours | Only an approved template | Charged per message by category |
This 24-hour period is the customer service window. See The 24-hour reply window.
#Templates
A template is a message you write once, submit to Meta for approval, and then send to many people or at any time. Templates can include a header (text, image, video or document), body text with variables like {{1}} for the customer's name, a footer and up to three buttons. See Create a template.
#Template categories
| Category | Use it for | Examples |
|---|---|---|
| Marketing | Offers, announcements, newsletters, re-engagement | "Our Diwali sale is live" |
| Utility | Updates about something the customer started | Order confirmations, appointment reminders, payment receipts |
| Authentication | One-time passcodes | "Your login code is 482913" |
Choose honestly. Meta reviews the category and may change it or reject the template.
#What messages cost
Meta charges per message for templates, by category. In India (2026), a marketing message costs more than a utility or authentication message. Nexora deducts these charges from your Messaging wallet and shows the cost before you launch a campaign. If a message fails to deliver, its cost is credited back. See Billing, wallets and charges.
Meta changes its rates and rules from time to time. Nexora always applies the current rules, and the Billing page shows exactly what you were charged.
#Consent
Only message people who have agreed to hear from your business, and make it easy to opt out. This is required by Meta and by India's data-protection rules. See Consent and messaging rules.
#Quality rating
Meta watches how customers react to your messages. Many blocks or reports lower your number's quality and can limit how many people you can message. See Protect your number's quality.