In India, TRAI categorizes bulk SMS into two types: Promotional and Transactional. So every business that uses SMS marketing should understand how they differ to ensure compliance and send the right messages to the right audience.

Quick Comparison: Promotional Vs Transactional SMS

The main difference between Promotional and Transactional SMS is intent.

Promotional SMS carries marketing or advertising content, while Transactional SMS delivers service-related or informational updates.

Here’s a brief overview.

Feature	Promotional SMS	Transactional SMS
Purpose	Marketing and Sales	Service messages
Timing	10 AM to 9 PM only	24/7 (Anytime)
DND Policy	Blocked on DND numbers	Delivered to DND as well
Sender ID	6-digit numbers	6-letter alphabetic
DLT Category	Promotional / Service Explicit	Service Implicit / Transactional
Allowed content	Offers, discounts, brand campaigns	Order updates, OTPs, alerts (no marketing)

What is Promotional SMS?

Promotional SMS are marketing messages used to promote products, offers, or brand campaigns. Their primary goal is conversion or engagement.

Key Rules of Promotional SMS:

Time window: Allowed only between 10:00 AM and 9:00 PM.
DND: Cannot be sent to numbers registered on Do Not Disturb (DND).
Sender ID: Must use a 6‑digit numeric header (brand name not allowed).
Consent: Requires prior customer permission to receive marketing messages.

Examples of Promotional SMS:

Flash Sale! 20% off on all shoes. Shop now: [Link]
Happy Diwali! Visit our store for a special gift.

What is Transactional SMS?

Transactional SMS deliver service-related or urgent information, typically triggered by a customer action (purchase, login, payment) or sent for essential service updates and reminders.

Key Rules of Transactional SMS

No time restriction: Can be sent 24/7.
Bypasses DND: Delivered even if the recipient is on DND.
Sender ID: Must use a 6-letter alphabetic header (e.g., TATAIN, HDFCBK)
No marketing content: Promotional offers, links, or advertising are prohibited in transactional templates and can cause message blocking and DLT account flagging

Examples of Transactional SMS:

Your order #552 has been packed and is ready for shipping.
Your OTP for login is 9876.
Parent–Teacher meeting for Grade 8 on June 10 at 4:00 PM in the school auditorium. Please arrive 10 minutes early – Greenfield High School.

How To Send: Promotional SMS Vs Transactional SMS

Both types can be sent via a web dashboard or an SMS API.

A web dashboard offers an interface for businesses to manually upload contacts, compose messages, add sender ID and schedule campaigns. Best for small scale and manual sends.

For large operations, integrating an SMS API allows connection with CRM or e-commerce platforms, enabling real-time triggers like order updates or personalized offers.

If you haven’t picked a provider, compare the top bulk SMS service providers in India to match delivery reliability and pricing to your needs.

DLT Compliance and Critical Rules (India)

Mandatory DLT registration: All businesses sending bulk SMS must register on a telecom DLT platform before sending messages.
Template approval: Every message template must be pre-approved on the DLT portal. Unapproved templates will be blocked.
Sender ID registration: Register your 6‑letter alphabetic header for Transactional SMS or 6-digit header for Promotional SMS.
No mixing: Transactional templates must not include marketing content. Violations can lead to message blocking, warnings, or DLT account suspension/flagging.

Summary: Promotional Vs Transactional SMS

Promotional SMS are sent with the purpose of promoting products/services or raising brand awareness.
Transactional SMS are service related messages which are purely informational.
Promotional SMS require the receiver’s consent before sending. Transactional SMS don’t need prior consent, but you must maintain a digital record of the user’s details (phone number, purpose/KYC source, and timestamps).
If someone consents to receive transactional SMS from your brand, they’re not by default consenting to receive promotional SMS too.

Need help with DLT registration, template approvals, or API integration? Contact Digimiles for professional setup and support.