How an SMS Gateway Works in India: Routes, DLT and API
An SMS gateway turns a message from your app, software or spreadsheet into an SMS on a customer's phone. Here is how it works in India, which route each message needs, what DLT asks of you and how to connect through the API.
An SMS gateway connects your website, app or software to mobile operators so you can send SMS in volume. In India it must use DLT-registered headers and templates, and it sends each message on a transactional, service or promotional route. We run direct Jio, Airtel, Vi and BSNL routes from ₹0.15 per SMS plus GST, with no monthly fee.
From ₹0.15 per SMS
Pay only for delivered SMS. No monthly platform fee. Plans start at 5,000 SMS.
Direct operator routes
Connectivity to Jio, Airtel, Vi and BSNL, backed by 6+ redundant routes.
DLT help included
We guide your PE, header and template registration with no service charge.
REST API and webhooks
HTTP/HTTPS and XML APIs with delivery reports pushed to your own URL.
What is an SMS gateway?
An SMS gateway is the bridge between your business software and the mobile networks. Your CRM, billing system or app sends a message request to the gateway through an API or a web panel. The gateway checks it against your DLT records, picks a route and hands it to the operator, which delivers it to the customer's phone. A delivery report then comes back, so you know which numbers received it and which did not.
Without a gateway you would need separate agreements with every telecom operator. With one, a clinic in Coimbatore and an exporter in Tiruppur can each send thousands of messages from a single login, in English or in Indian languages such as Tamil and Hindi.
Behind the panel, the gateway also handles character encoding and splits long messages into parts that the phone joins back together, so a long Tamil notice still reads as one message.
SMS routes in India: transactional, service and promotional
TRAI rules sort every commercial SMS by purpose. The category decides who you can reach and at what time.
Since 6 May 2025 operators add the suffix to your 6-character header, so a customer sees AD-ACMEIN-S or AD-ACMEIN-P and can tell an alert from an offer at a glance. Picking the right category at registration saves you from blocked messages later.
Register separate templates for each purpose instead of one generic text. A school, for example, might register one service template for fee reminders, one for exam alerts and one promotional template for its admission campaign.
- Transactional (-T): OTPs and critical account alerts. Delivered to DND numbers at any hour with an approved template.
- Service (-S): order updates, reminders, receipts and other messages a customer expects. Also reaches DND numbers any time.
- Promotional (-P): offers and announcements. Only for non-DND numbers or customers with digital consent, between 10am and 9pm.
DLT compliance with an SMS gateway provider in India
Every business that sends commercial SMS must register as a Principal Entity on an operator DLT portal, then register its headers and content templates. One registration works across all operators. The operator charges about ₹5,900 including GST for PE registration (about ₹3,300 on the BSNL portal) and about ₹590 per header per year. Templates are free, and approval usually takes 2 to 7 working days.
Our team works through the forms with you, free of service charge. We help you write templates with {#var#} fields that match your real messages, map each header to the right category and whitelist the URLs and call-back numbers you plan to use. Since 1 October 2024, links that are not whitelisted, including public URL shorteners, are blocked, so this step matters.
Already registered on a DLT portal with another provider? You do not need to start again. Share your entity ID, headers and template IDs, and we link them to your account.
SMS gateway API for developers
Developers connect through an HTTP/HTTPS REST API or an XML API. Send a single OTP or a batch of lakhs of numbers, pass personalised variables, schedule sends and receive delivery reports on your own webhook. The platform handles up to about 10,000 SMS per second, so a flash sale or a results day does not build a long queue.
Prefer no code? Upload an Excel or CSV file in the web panel, or connect Zoho, HubSpot, WooCommerce, Shopify, WordPress or Google Sheets through webhooks, Zapier or Pabbly Connect.
Delivery reports are the part many buyers overlook. Each message returns a status such as delivered, failed or pending, so your team can fix a wrong number or a template mismatch instead of guessing.
How to choose an SMS gateway, and why businesses pick us
Ask every provider the same questions before you sign up:
AvanceZone Technology has worked in bulk SMS since 2000, has served 5,000+ businesses and handles 1 billion+ messages a year. We run to a 99.9% platform uptime target, sell credits from 5,000 SMS that stay valid for a year, and our Coimbatore team answers on phone and WhatsApp from Monday to Saturday. Starter suits a shop or clinic sending a few thousand SMS a month. Business suits growing brands and software platforms. Enterprise suits banks, large retailers and apps that need an SLA.
- Is pricing per delivered SMS, and does the quote include GST?
- Which operators do they connect to directly, and is there a backup route?
- Will they help with DLT, or just send you a PDF guide?
- Do they give real-time delivery reports and an API with webhooks?
- What is the minimum purchase, and how long do credits last?
- Who picks up the phone when a campaign is stuck?
Sending outside India too?
We also send SMS and WhatsApp messages to customers abroad, with help on each country's sender ID and consent rules.
How it works
Create your free account
Sign up online, recharge from 5,000 SMS and get access to the web panel and API.
Finish DLT registration
Register your PE, header and templates with our help, or link the DLT IDs you already have.
Connect and send
Plug in the API, or upload a contact sheet and send from the web panel.
Track and scale
Watch delivery reports live and move to Business or Enterprise pricing as volume grows.
Frequently asked questions
Which is the best SMS gateway provider in India?
The right choice depends on your volume and use case. Look for direct operator connectivity, DLT support, a documented API, real-time delivery reports, clear per-SMS pricing and support you can actually reach. We cover each of these, charge from ₹0.15 per SMS with no monthly fee, and start plans at 5,000 SMS so you can test with a small purchase.
How much does an SMS gateway cost in India?
Our pricing is pay-as-you-go. Starter costs ₹0.20 per SMS for up to 10,000 SMS a month. Business costs ₹0.15 per SMS for up to 1,00,000 SMS a month. Above that, Enterprise pricing is custom. Prices exclude 18% GST and you pay only for delivered SMS. DLT registration fees are paid to the operator separately.
Can I send SMS in India without DLT registration?
No. Under TRAI's TCCCPR 2018 rules, commercial SMS must come from a registered Principal Entity using an approved header and content template. Operators block messages that do not match a registered template. We help you complete DLT registration without any service charge, and you pay only the operator's own registration and header fees.
How fast are SMS delivered through your gateway?
Most messages are typically delivered in a few seconds. The exact time depends on the operator and whether the handset is switched on and in coverage. The platform can push up to about 10,000 SMS per second, and you can see the status of every message, delivered, failed or pending, in the delivery report.
Can I send SMS to DND numbers?
Yes, if the message is transactional or service and uses an approved DLT template. OTPs, order updates, reminders and account alerts reach DND numbers at any time of day. Promotional SMS can only go to non-DND numbers or to people who gave digital consent, and only between 10am and 9pm.
Do you provide an SMS gateway API?
Yes. You get an HTTP/HTTPS REST API and an XML API that support personalised variables, scheduling and delivery report webhooks. Starter includes basic API access, while Business and Enterprise include the full API. If you would rather not code, the web panel, Excel upload and integrations with Zapier, Pabbly Connect, Zoho and Shopify cover most needs.
Send your first SMS today
From ₹0.15 per delivered SMS, credits valid for a year, and DLT help from a real person.