SMS is short, fast and gets seen almost immediately. Email is slower but has room for detail, images and links. So SMS suits urgent, simple messages, and email suits anything that needs explaining. Most businesses that use both well keep them for different jobs.
What SMS is good for
Appointment reminders. Order and delivery updates. OTPs. A short alert about a limited offer. Messages people expect and want quickly.
It's poor at anything long. You get a few lines, no images and very little room to persuade.
What email is good for
Newsletters, guides, follow-up sequences for new enquiries, product launches and anything where the reader needs more than one sentence to decide. You can segment your list, test subject lines and see who clicked.
The weakness is attention. Inboxes are crowded, and some emails land in promotions or spam.
The rules in India
Commercial SMS in India runs under TRAI's DLT system. Businesses have to register, and messages go out using approved headers and templates. Your SMS provider will usually guide you through this, but plan for the setup time.
Email has fewer formal registration steps, but good practice still matters. Send only to people who agreed to hear from you, make unsubscribing easy and set up SPF, DKIM and DMARC for your domain. India's data protection rules are also being phased in, so check consent requirements with your legal adviser.
Cost
SMS is charged per message, which adds up on large lists. Email platforms usually charge by list size or volume, and the cost per message is often lower. Compare cost per sale, not cost per message.
Using them together
A sensible setup for many businesses looks like this. SMS for reminders and urgent updates. Email for nurturing, education and offers. WhatsApp increasingly fills the gap between them for conversations.
Don't send the same promotion on every channel at once. That's how people end up blocking you.
See my email marketing services, or read the email marketing guide.
Written by Aman Potlia.