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OTP SMS that arrives while your customer is still on the screen.
Send one-time passwords for logins, payments and sign-ups on a high-priority transactional route, under your own brand name.
Built for the moment that matters.
A login or payment fails if the code is late. Transactional SMS on Unecast goes out with high delivery priority and reports its status back to you.
- High-priority transactional route for codes and alerts.
- Delivery status by message ID.
- Balance API so your system can top up in time.
Ten lines of code.
Send with one POST request and check status with one GET. Bearer token authentication keeps it simple.
- REST API for apps and websites.
- SMPP for high-volume platforms.
- Sandbox testing with our team during setup.
# Send a transactional SMS curl -X POST https://api.unecast.com/v2/send \ -H "Authorization: Bearer YOUR_TOKEN" \ -H "Content-Type: application/json" \ -d '{ "channel": "sms", "from": "YOURBRAND", "to": "94771234567", "message": "Your OTP is 482913", "priority": "high" }'
Add WhatsApp as a second channel.
WhatsApp authentication templates can deliver codes inside WhatsApp, with SMS as a fallback, all from one provider.
- Authentication templates on your verified number.
- One account for SMS and WhatsApp.
- Zero markup on Meta's fees.
Frequently asked questions
How much does an OTP SMS cost?
OTPs are sent as transactional SMS on a high-priority route. Pricing depends on the destination and route: for Sri Lanka, businesses there pay LKR 0.50 each including government taxes, and senders from abroad use the HQ ($0.105) or Wholesale ($0.078) routes; the $0.0025 Premium local route is for businesses incorporated in Sri Lanka.
Can I send OTPs on WhatsApp instead of SMS?
Yes. WhatsApp authentication templates deliver one-time passwords inside WhatsApp. Many businesses use WhatsApp first and SMS as a fallback.
How do I integrate OTP SMS?
Call the REST API with your sender ID, the number and the message, and read the delivery status by message ID. High-volume platforms can use SMPP.
Can the sender ID be my brand name?
Yes. We register your brand as the sender ID during setup, so customers recognise every code.
Get your OTP route live.
Book a 30-minute walkthrough with our team. We will show you the inbox, an AI agent and campaigns using your products and questions.