SMS Overview

Exotel provides a reliable SMS platform that enables businesses to send transactional, promotional, and OTP messages across India. This guide covers the fundamentals of Exotel's SMS service, including message types, delivery infrastructure, and regulatory compliance.

tip

For API-level documentation on sending SMS programmatically, see the SMS API Reference.

How Exotel SMS Works

Exotel acts as an aggregator between your application and Indian telecom operators. When you send an SMS through Exotel, the message flows through the following path:

Your Application → Exotel API → DLT Scrubbing → Telecom Operator → Recipient Handset

1. Message Submission -- Your application sends an SMS request via the Exotel API or dashboard.
2. DLT Validation -- The message is validated against your registered DLT templates and sender IDs.
3. Operator Routing -- Exotel routes the message to the appropriate telecom operator.
4. Delivery -- The operator delivers the message to the recipient's handset.
5. Status Callback -- Exotel sends a delivery report back to your configured webhook.

SMS Types

Exotel supports three categories of SMS, each with different delivery rules and regulations:

Type	Use Case	Delivery Window	DND Applicable
Transactional	OTPs, alerts, order updates, banking notifications	24/7	No
Transactional Opt-in	Transactional messages requiring user consent	24/7	No
Promotional	Marketing offers, discount campaigns, product launches	9 AM -- 9 PM	Yes

warning

Promotional SMS cannot be delivered to numbers registered on the National Do Not Disturb (NDNC/DND) registry. Use transactional SMS for critical communications.

Key Features

• High Throughput -- Send thousands of messages per second with Exotel's enterprise-grade infrastructure.
• DLT Compliance -- Built-in support for TRAI's DLT regulations including entity registration, template approval, and consent management.
• Delivery Reports -- Real-time delivery status via webhooks or API polling.
• Bulk Messaging -- Send the same or unique messages to up to 100 recipients in a single API call.
• URL Shortening -- Shorten and track links within your SMS messages.
• Unicode Support -- Send messages in Hindi, Tamil, and other regional languages.
• Two-Way SMS -- Receive inbound SMS and build interactive workflows.

Prerequisites

Before you start sending SMS with Exotel, ensure you have:

1. An active Exotel account -- Sign up here if you do not have one.
2. DLT Registration -- Register as an entity on a DLT portal (Jio, Airtel, Vodafone-Idea, or BSNL). See DLT Registration.
3. Approved Sender ID -- Register your sender ID (header) on the DLT portal. See Sender ID.
4. Approved Templates -- Get your message templates approved on the DLT portal. See SMS Templates.
5. API Credentials -- Obtain your API key and token from the Exotel Dashboard.

Sending Your First SMS

You can send SMS through Exotel in two ways:

Via the Dashboard

1. Log in to the Exotel Dashboard.
2. Navigate to App Bazaar > SMS.
3. Select Send SMS.
4. Choose the sender ID, enter the recipient number, select a template, and click Send.

Via the API

Use the Send SMS API to send messages programmatically:

curl -X POST "https://<api_key>:<api_token>@api.exotel.com/v1/Accounts/<account_sid>/Sms/send" \
  -d "From=EXOTEL" \
  -d "To=+91XXXXXXXXXX" \
  -d "Body=Your OTP is 123456" \
  -d "DltEntityId=XXXXXXXXXXXXX" \
  -d "DltTemplateId=XXXXXXXXXXXXX"

Rate Limits

Limit	Value
API calls	200 requests/minute
Bulk SMS per request	100 messages max

Regional Endpoints

Region	Subdomain
Singapore	api.exotel.com
Mumbai	api.in.exotel.com

Next Steps

• How to Send SMS -- Step-by-step sending guide
• SMS Templates -- Create and manage message templates
• DLT Registration -- Register with a DLT portal
• SMS Delivery Reports -- Track message delivery
• SMS API Reference -- API documentation