Both channels reach almost every phone in India, but they behave very differently once a message actually lands — and the gap has widened as WhatsApp usage has grown.
SMS messages sit in a generic inbox that's increasingly filled with OTPs, spam, and promotional clutter that people scan past without reading closely. WhatsApp messages arrive in the same app people use to talk to friends and family — that context alone drives noticeably higher open and read rates, which is widely reported across the industry as one of WhatsApp's biggest advantages over SMS for anything beyond a bare OTP.
SMS is 160 characters of plain text, full stop. WhatsApp messages can include images, PDFs, buttons ("Track Order," "Call Us," "View Menu"), and formatted text — meaning a single WhatsApp message can do what would take an SMS plus a follow-up link click to a separate landing page. A delivery update with a photo of the packed order, or a menu sent as an actual PDF, simply isn't possible over SMS.
Replying to an SMS is rare and clunky — most people never do it. Replying to a WhatsApp message is completely normal; customers can ask a follow-up question right in the same thread, which SMS was never built for. This is what makes WhatsApp usable for actual support conversations, not just one-way notifications.
WhatsApp supports interactive elements SMS can't — quick-reply buttons, list menus, and full in-chat forms (WhatsApp Flows) for things like appointment booking or lead capture, with real-time field validation. A chatbot can hold an actual branching conversation on WhatsApp; on SMS, every reply is just unstructured text you'd have to parse manually.
This is where it's closer to a wash: WhatsApp's conversation-based pricing (see our pricing explainer) can be cheaper or more expensive than SMS depending on message category and volume — it's not a universal win on price alone, and businesses sending very high volumes of simple text-only alerts should actually compare both on a per-message basis for their specific use case.
SMS doesn't require the recipient to have an internet connection or WhatsApp installed, so for reaching feature-phone users or areas with poor data coverage, it remains more reliable as a fallback. It's also still the default channel for OTPs in India, since it doesn't depend on an app being open or notifications being enabled.
Most Indian businesses get the best results using WhatsApp as the primary channel for anything expecting engagement — orders, support, marketing — and keeping SMS as a backup for critical, must-deliver messages where a fallback channel matters more than richness or reply rate.
Most businesses don't switch overnight — they run both for a period, moving the message types that benefit most from WhatsApp's richness (order updates, marketing, support) first, while leaving OTP and critical alerts on SMS until they're confident in WhatsApp delivery for their audience. Importing your existing SMS contact list as WhatsApp contacts (with consent) is usually the first practical step, followed by testing a single message type — order confirmations are a common starting point — before expanding further.
Whichever channel you use, sending marketing messages to someone who hasn't consented is both against WhatsApp's own policies and generally poor practice. WhatsApp's opt-in requirements are stricter than SMS in some respects, but the payoff is a list of people who actually want to hear from you — which is part of why engagement tends to be higher in the first place.
Rather than relying on general industry claims about open rates, the most reliable way to know which channel performs better for your specific customers is to run the same offer through both channels to a comparable segment and compare delivery, read, and response rates directly — your audience's phone habits are the only data that actually matters for your decision.
SMS marketing tools are typically one-directional blast senders with limited reporting beyond delivery status. A WhatsApp platform brings a shared team inbox for replies, a template manager with approval tracking, and campaign-level reporting — closer to a full communication system than a simple send-and-forget tool, which matters once a business's WhatsApp volume grows beyond the occasional promotion.
Q: Is WhatsApp always cheaper than SMS? A: Not universally — it depends on template category and your volume. It's worth comparing for your specific message mix rather than assuming.
Q: Can customers reply to a WhatsApp marketing message the way they can't with SMS? A: Yes, and that two-way capability is one of the main practical differences — a WhatsApp thread supports genuine back-and-forth, SMS doesn't.
Q: Should I drop SMS entirely? A: Usually not — keep it for OTPs and as a fallback for the portion of customers without WhatsApp access.