WhatsApp OTP and Transactional Messaging API for Developers and Businesses
Instant Broadcast's WhatsApp OTP and transactional messaging API lets your app, website or backend send one-time passwords, order alerts, payment confirmations and account updates on WhatsApp through a simple REST API, on Meta's official WhatsApp Business Cloud API. On our India rate card, authentication (OTP) and utility messages cost ₹0.15 each.
What the WhatsApp OTP and Transactional Messaging API Covers
Transactional messages are messages a customer expects because of something they did. They aren't promotions. On WhatsApp they fall into two template categories:
- Authentication: one-time passwords for login, sign-up, payment or account verification.
- Utility: order confirmations, shipping and delivery alerts, payment receipts, invoice reminders, booking confirmations and account or security notices.
WhatsApp OTP vs SMS OTP
| SMS OTP | WhatsApp OTP | |
|---|---|---|
| Sender shown | A sender ID | Your business name on WhatsApp |
| Copy-code button | No | Yes, with a copy-code button template |
| Delivery status | Delivered | Sent, delivered and read |
| Rich follow-ups | Text only | Buttons, links and replies in the same chat |
| Rate (Instant Broadcast, India) | Depends on SMS provider | ₹0.15 per authentication message |
Many businesses use WhatsApp as the main OTP channel and keep SMS as a fallback for users without WhatsApp.
How the API works
- Connect your number to the official WhatsApp API through Instant Broadcast, starting with the 7-day free trial.
- Create templates for your OTP and alert messages and get them approved by Meta.
- Get your API credentials from Instant Broadcast.
- Call the REST API from your backend with the recipient number, the template name and the variable values, such as the OTP code or order ID.
- Track status: sent, delivered, read or failed.
Our team shares API documentation and helps your developers test the integration.
Common transactional use cases
- Fintech and payments: login OTPs, payment receipts, failed-payment alerts.
- E-commerce: order, shipping and delivery updates; COD confirmation.
- SaaS and apps: sign-up verification, password resets, security alerts.
- Travel and bookings: booking confirmations, schedule changes, e-tickets.
- Healthcare and services: appointment confirmations and reminders.
- Distributors and B2B: invoice and payment-due reminders.
Best practices
- Keep transactional templates free of promotions, or Meta may class them as marketing, at ₹1.12 per message.
- Set short OTP expiry times and never ask users to share the code.
- Collect opt-in for WhatsApp notifications in your sign-up or checkout flow.
- Handle failures: fall back to SMS when WhatsApp delivery fails.
- Monitor delivery rates and investigate any spikes in failures.
Read more about the official WhatsApp API for business messaging and our WhatsApp API integration service.
Official references: Meta’s guide to WhatsApp message templates and the WhatsApp Business Messaging Policy.
Frequently asked questions
Can I send OTPs on WhatsApp?
Yes. Use an approved authentication template and send the OTP through Instant Broadcast's REST API on the official WhatsApp Business API.
How much does a WhatsApp OTP cost in India?
Authentication messages cost ₹0.15 each on the Instant Broadcast rate card for India. Utility messages are also ₹0.15.
What is a transactional WhatsApp message?
A message the customer expects because of an action they took, such as an OTP, order confirmation, payment receipt or booking update.
Is WhatsApp OTP better than SMS OTP?
WhatsApp shows your business name, supports a copy-code button and reports read status. Many businesses keep SMS as a fallback for users without WhatsApp.
Do I need a developer?
Yes, to call the REST API from your app or backend. Our team shares documentation and helps with testing.
Do transactional messages need templates?
Yes. OTP and alert messages sent by your business must use templates approved by Meta.
Can I track whether a message was delivered?
Yes. You can see whether each message was sent, delivered, read or failed.
Is there a free trial?
Yes. You can test the API during the 7-day free trial.