SMS, Email, Push or RCS: Routing Messages in Indian Commerce

Channel choice in Indian commerce is usually made backwards. A team picks the channel the platform makes easiest, writes the message, then discovers the economics after the invoice arrives. The better order is the opposite. Decide what the message is worth, decide how urgently it must land, and let those two facts pick the channel.

Here is what each channel actually is, stripped of vendor framing.

SMS: guaranteed reach, regulated hard, priced per send

SMS is the only channel that reaches a customer without an app, without an inbox login, and without a data connection. That reach is genuinely valuable in tier two and tier three India, and it is why the channel refuses to die.

The constraint is regulatory and it is structural. Commercial SMS in India runs through an entity registration and template approval framework administered via the telecom operators. You register as a principal entity, register your sender identifier, and register each message template with variable fields declared. Traffic that does not match an approved template gets scrubbed at the operator. Transactional and service content follows a different approval route from promotional content, and misclassifying promotional copy as transactional is how brands lose delivery silently.

Three practical consequences. First, SMS has a lead time. You cannot write a campaign on Tuesday and send it Tuesday. Template approval sits between idea and send, so your calendar has to run ahead of itself. Second, your copy is not free form. Variables are declared in advance, so a template written narrowly cannot be reused broadly. Build a template library deliberately. Third, promotional SMS is subject to preference and scrubbing rules that will silently reduce your addressable base below your list size.

Rules, categories and commercial terms in this framework change. Confirm the current requirements with your provider and your registered operator rather than working from any static summary, including this one.

Cost characteristics: priced per send, promotional and transactional priced differently, and the price is per message rather than per person reached. A three message sequence to a hundred thousand contacts is three hundred thousand paid sends whether or not anyone reads them.

Email: the only channel you own

Every other channel is rented. App stores control push. Operators control SMS. Platforms control their own messaging surfaces and change the rules unilaterally. Email is a list of addresses that sits in your database and moves with you if every vendor relationship ends tomorrow.

Cost is effectively per thousand and low enough that message length and creative richness are free. This is the channel for the itemised order record, the long form content, the multi product merchandising, and anything a customer might want to find again in six months.

The catch is deliverability, and it is earned rather than bought. Inbox placement depends on your authentication records being correct, your sending domain having a consistent reputation, and above all your engagement rates. Send to people who do not open, and the mailbox providers route you to promotions or spam for everyone, including the people who do open. This is why list hygiene is a deliverability lever and not a tidiness exercise.

Practical read: email survives because you own it, but only if you protect the reputation attached to it.

Push: free at the margin, worthless when uninstalled

Push has the best unit economics of any channel. There is no per send cost worth modelling. That single fact leads teams to over send until the channel stops working.

The real problem with push in India is denominator honesty. Your addressable push base is not your install count. It is installs, minus uninstalls, minus users who never granted notification permission, minus users on devices where aggressive battery management suppresses delivery. On a typical Indian consumer app that chain can cut the reachable base to a fraction of the installed base, and the uninstalled users are invisible to your dashboard because a token that no longer resolves does not throw an error you look at.

So push is excellent for engaging active users and structurally incapable of reactivating lapsed ones. The customer you most want to win back is precisely the customer who deleted the app. Any reactivation plan built on push is measuring itself against a base that has already left.

RCS: better canvas, uneven ground

RCS gives you branded sender identity, rich cards, images and buttons inside the default messaging app, with delivery and read signals. It behaves like a modern messaging surface without requiring an app install.

Treat it as an upgrade path rather than a foundation. Availability depends on the handset, the operating system and operator support, so your reachable base varies by segment and shifts over time. Build it as a preferred channel with a defined fallback, so a message that cannot render as RCS still lands as SMS. Do not design a flow that only works if RCS renders.

WhatsApp sits alongside these with its own template rules and per conversation pricing model, which we cover separately on this site.

Routing by urgency and value

Two variables decide the channel. How fast must this land, and what is the message worth if it works.

High urgency, high value: out for delivery on a cash on delivery order, a failed payment on a subscription renewal, a delay on a gifting order. Send on the channel with the highest guaranteed reach and accept the per send cost. Usually SMS, with push as a parallel send for active app users.

High urgency, low value: a flash window closing. Push first, because the cost is near zero and the audience is by definition active. Do not buy SMS for this.

Low urgency, high value: the order record, the return instructions, the replenishment reminder on a high ticket consumable. Email, because detail matters more than speed and you own the channel.

Low urgency, low value: newsletters, general merchandising, category education. Email only, and inside a frequency cap. This is the quadrant where brands burn deliverability for very little.

Build the routing into the system, not the brief

Encode this. Every message type in your library gets a declared urgency tier, a declared value tier, a primary channel and a fallback rule. When a new campaign is requested, the channel is looked up rather than argued about.

Then measure per channel and per message type: reach as a share of intended audience, cost per delivered message, and downstream action rate. Reach is the number teams forget. A channel with a great click rate on a base that is a fifth of your customers is not performing well. It is performing narrowly.