Transactional SMS Service & API — OTPs and Alerts Delivered in Seconds, 24×7, Even on DND
Send OTPs, order updates and account alerts your customers actually expect — over DLT-registered, TRAI-compliant direct operator routes to Airtel, Jio and Vi, plus 190+ countries worldwide. Sub-5-second OTP delivery with real-time delivery reports.
What is transactional SMS?
Transactional SMS is an automated, non-promotional message triggered by a user action or account event — an OTP, an order confirmation, a payment alert or an appointment reminder. Because the content is information the recipient expects, transactional SMS can be delivered round the clock, including to DND (NDNC-registered) numbers, unlike promotional messages which are time-restricted and require explicit opt-in.
For businesses in India, every transactional message travels over routes registered on a DLT (Distributed Ledger Technology) platform under TRAI rules, using an approved 6-character sender ID (header) and a pre-approved content template — guaranteeing authenticity and high deliverability. We handle that entire compliance layer for you.
Transactional vs promotional SMS
Both use the same 160-character channel, but the rules, timing and use cases are very different. Sending the wrong type on the wrong route gets your messages blocked.
| Aspect | Transactional SMS | Promotional SMS |
|---|---|---|
| Purpose | Essential, user-triggered information | Marketing, offers, brand awareness |
| Trigger | User action / account event (automated) | Business-initiated campaign |
| DLT category | Service (implicit / explicit) | Promotional |
| Delivery timing | 24×7, any time | 9 AM–9 PM IST only |
| DND numbers | Delivered (bypasses NDNC) | Blocked for DND users |
| Consent | Implicit (via the transaction) | Explicit opt-in mandatory |
| Content | Information only — no promo language | Offers, discounts, coupon codes |
| Typical open rate | ~95–98% | ~30–40% |
| Examples | OTP, shipping alert, payment confirmation | “25% off — use code SAVE25” |
Running a marketing campaign instead? See our promotional SMS gateway.
How transactional SMS works
From a trigger in your app to a delivery report in your dashboard — in about five seconds.
Trigger
A user logs in, checks out or books — your app fires an API call.
Gateway
Our SMS gateway validates the DLT header & template and picks the fastest route.
Operator SMSC
A direct bind to Airtel/Jio/Vi (or a global carrier) accepts the message.
Handset
The message lands on the customer’s phone, usually within seconds.
Delivery report
A real-time DLR (delivered / failed) returns to your dashboard & webhook.
Transactional SMS use cases
OTP & 2FA
One-time passwords and two-factor authentication codes on the highest-priority route.
Order & delivery alerts
Order placed, shipped, out-for-delivery and delivered notifications.
Banking & payment alerts
Debit/credit confirmations, balance updates and fraud alerts for BFSI.
Appointment reminders
Cut no-shows with automated reminders for clinics, salons and services.
Account notifications
Password changes, profile updates and service status messages.
Healthcare & alerts
Test results, prescription reminders and critical internal alerts.
Key features of our transactional SMS gateway
Priority OTP routing
Dedicated high-priority queue for sub-5-second OTP delivery.
Intelligent retry & failover
Automatic re-routing to an alternate operator route during outages.
Real-time delivery reports
Per-message DLR — delivered, failed or pending — via dashboard & API.
Unicode & regional languages
Send in Hindi, Tamil and 20+ languages with full Unicode support.
Registered sender IDs
DLT-approved 6-character headers so customers recognise you instantly.
Link shortener & analytics
Trackable short links with click analytics on secure transactional URLs.
Secure & compliant
Encrypted API, OTP log redaction and TRAI/DLT-compliant delivery.
Dashboard & scheduling
Live analytics, campaign logs and schedule-ahead sending.
SMS API & easy integration
Fire a transactional SMS on any event with a single REST call, or bind over SMPP for high-throughput traffic. Get delivery receipts back through webhooks.
- REST & SMPP APIs with SDKs for PHP, Python, Node.js, Java and .NET
- Webhook / DLR callbacks for real-time delivery status
- Ready plugins for WooCommerce, Shopify and WordPress
- Sandbox keys, clear docs and 24×7 integration support
DLT registration & TRAI compliance — handled for you
TRAI requires every business sending SMS in India to register on a DLT platform. Miss a step and operators block your messages. We register and manage all of it so you go live faster.
1. Principal Entity (PE-ID)
Register your business as a Principal Entity on the DLT portal to get a unique entity ID.
2. Sender ID / header
Register your 6-character alphabetic header (e.g. SGWPRV) for transactional traffic.
3. Content templates
Pre-register each message template — even a one-word change needs its own approval.
4. Consent & category
Map templates to the right service category so they route and deliver correctly.
Need help registering? Explore our DLT registration & support services.
OTP SMS built for speed and security
Every OTP is a transactional message — but not every transactional message is an OTP. We route verification codes through a dedicated high-priority queue so logins and payments never stall.
- Sub-5-second delivery on direct operator routes
- Automatic failover to an alternate route if the first is slow
- OTP redaction in logs and optional voice-OTP fallback
“Your OTP is 480216. Valid for 10 minutes.”
Delivered in 3.1sA transactional SMS partner you can rely on
Trusted by 5,000+ businesses across India and 190+ countries, backed by 15+ years in messaging — with direct operator routes, real compliance support and the delivery proof buyers look for.
Direct operator routes
Direct binds with Airtel, Jio and Vi in India plus 190+ countries for the shortest path to the handset.
99.9% uptime
Redundant infrastructure with intelligent retry keeps critical messages flowing.
DLT done for you
We register your entity, headers and templates — a service most global providers don’t offer.
24×7 human support
Real integration and delivery support whenever you need it, day or night.
How to get started
1. Create your account
Sign up and share your business details to begin onboarding.
2. Register DLT & sender ID
We help you get your entity, header and templates approved.
3. Integrate & go live
Drop in the API or a plugin, send a test OTP and start delivering.
