Transactional SMS

Transactional SMS that delivers in <3 seconds

OTPs and customer alerts 24×7 on priority routes. Sub-3-second delivery, webhook callbacks, all networks including DND.

Why it matters

When delivery time decides whether you win or lose

An OTP that arrives 30 seconds late costs you a signup. A payment alert that doesn't show up costs you trust. Transactional SMS is the channel where speed and reliability aren't features, they're the product.

Step 1
Your app fires the API call
POST /api/sendsms.php with template ID, recipient and OTP.
Step 2
SmsHorizon routes via priority telco
Best route picked across Airtel, Jio and Vi with automatic failover.
Step 3
OTP lands on the customer's phone
Sub-3-second delivery, even on DND-registered numbers.
Step 4
Webhook fires back to your endpoint
JSON payload with delivery status and timestamp. Callback arrives within 10 seconds. No polling needed.
OTP in under 3 seconds. Delivery callback within 10 seconds.
Features

Built for mission-critical messaging

The infrastructure that powers OTPs for fintechs, alerts for hospitals and notifications for India's busiest e-commerce platforms.

Sub-3-second delivery

Direct telco connectivity and priority routes mean your OTPs land in 2 to 3 seconds, not 30. The difference between a completed signup and an abandoned one.

24×7 delivery

No time restrictions, including DND numbers.

Webhook callbacks

Real-time delivery status pushed to your endpoint.

Multi-operator routing with automatic failover

Redundant routes across Airtel, Jio and Vi. If a route degrades, traffic re-routes automatically without you lifting a finger or losing a message.

DLT compliant

Fully TRAI-aligned routes.

REST & HTTP API

Plug-in in minutes, any language.

Custom sender ID

6-char DLT-registered header.

High throughput

Up to 1,000 SMS/sec on enterprise.

Use cases

Who relies on transactional SMS

Any business that needs to reach a customer with information they're actively waiting for.

Banking & finance

Debit/credit alerts, balance updates, EMI reminders, statement notifications and loan disbursal updates.

Insurance

Policy issuance, renewal reminders, premium-due alerts, claim status updates and KYC notifications.

Stock brokers

Order confirmations, margin calls, contract notes, pay-in reminders and SEBI-mandated trade alerts.

Hotels & resorts

Booking confirmations, check-in details, room-ready alerts and post-stay receipt and feedback links.

Education

Attendance alerts to parents, fee reminders, exam-schedule updates and result notifications.
FAQs

Transactional SMS questions

What is transactional SMS?
Transactional SMS is time-sensitive, customer-initiated messaging: OTPs, payment alerts, order updates, appointment reminders and service notifications. Unlike promotional SMS, it delivers 24×7 on all networks including DND-registered numbers.
How fast do OTPs and alerts deliver?
Typically 2 to 3 seconds from the moment your API call hits us. Direct telco connectivity and priority routes keep latency consistently low, even during peak traffic windows.
Does it work on DND-registered numbers?
Yes. Transactional SMS is exempt from DND restrictions because it carries information the recipient has explicitly asked for (an OTP, an order update, a payment alert). All Indian networks honour this.
Do you support webhook callbacks for delivery status?
Yes. Configure a callback URL in your account and we'll POST a JSON payload to it the moment each message changes state (sent, delivered, failed). No polling, no DLR-pull script needed.
Is DLT registration required?
Yes, per TRAI rules. You need to register your entity, sender headers and message templates on the DLT portal. We assist with the entire process free of charge and typically have you live in 24 to 48 hours.
What sending throughput can I expect?
100 SMS/sec on standard accounts. Enterprise plans go up to 1,000 SMS/sec for high-volume OTP and alert traffic. Burst capacity is available on request.
What happens if a route fails mid-send?
Traffic re-routes automatically through redundant operator paths. We monitor route health continuously and pull bad routes out of rotation within seconds, so your messages keep flowing.
Can I use my own brand name as the sender?
Yes. A 6-character DLT-registered sender ID like AD-HORIZN puts your brand name on every message. Our team handles registration end-to-end.
How much does transactional SMS cost?
Transactional SMS is priced by volume and starts as low as 14 paise per SMS with good volume. See our pricing page for all plans, or talk to sales for a quote tailored to your usage.
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Start sending transactional SMS today

Test OTP delivery on your own number in under 2 minutes. We'll help you with DLT registration and have you live within 48 hours.

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Across India

Bulk SMS in India's major cities

We serve businesses in every major metro, with the same panel, API and pricing everywhere.

Bulk SMS in Mumbai Maharashtra
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