SMS and WhatsApp both reach a phone within seconds, which is where the similarity ends. One works on every handset and carries plain text; the other needs the app and carries media, buttons and a conversation. This guide compares them on reach, rules, format, replies, pricing and fit, so you can pick a channel per use case rather than per fashion.
Read alongside this guide: WhatsApp marketing software and Waki plans and pricing.
Key takeaways
- SMS reaches every phone; WhatsApp reaches people in the app with richer messages.
- Both need registered or approved templates and consent; WhatsApp adds two-way conversation.
- SMS is per message, WhatsApp per conversation; the models reward different behaviour.
- Use SMS as a fallback and for basic phones, WhatsApp where media, buttons or replies help.
Reach
SMS reaches any phone, including feature phones and people who never installed WhatsApp. WhatsApp reaches people who use the app, which in India covers a great many customers but not all of them. For an audience that includes feature phones, SMS still matters; for a smartphone audience, WhatsApp is where they already are.
Rules
Commercial SMS in India runs through the DLT system: registered sender headers, registered templates and consent records enforced by the operators. WhatsApp runs through Meta: opt-in from the customer, templates approved by Meta, and a quality rating on your number. Both channels require templates and consent; WhatsApp adds the two-way conversation and the customer-service window.
Format
An SMS is plain text with a character limit and raw links. A WhatsApp message shows your business name, can carry an image, a PDF or a video, offers reply and link buttons, and keeps the whole history in one thread. For a confirmation code the plain text is enough; for a brochure, a tracking link or a choice, WhatsApp does more.
Replies
SMS is effectively one-way for most businesses. On WhatsApp a reply opens a conversation that your team handles from a shared inbox or that a flow answers. That changes what you can send: a question becomes acceptable because an answer is possible.
Pricing model
SMS is priced per message sent. Meta prices WhatsApp per conversation and category, not per message, and bills it separately from your platform subscription. A back-and-forth with a customer inside one conversation costs the same whether it is one message or ten, which rewards dialogue and penalises blasting.
Where each fits
A sensible split looks like this.
- SMS for one-time passwords as a fallback and for audiences on feature phones.
- WhatsApp for anything that benefits from media, buttons, a document or a reply.
- WhatsApp for support and sales conversations; SMS is poor at both.
- Both for critical notices where you want a second route if one fails.
Next steps
Conclusion
Pick by use case. SMS stays useful where reach or fallback matters; WhatsApp wins wherever a message benefits from a picture, a button or an answer. Collect consent for each, and let the replies decide which channel earns more of your messages.