RCS vs WhatsApp Business API

Side by side

The difference that decides most cases: opt-in

Everything else on that table is a feature comparison. This one is a business-model difference, and it usually settles the question.

WhatsApp is a permission channel. Before you send a customer their first message, you need an opt-in in which your business is clearly named and an opt-out is available, and if Meta asks, the burden of proving that consent is yours. That is a real constraint on a list you built through years of orders and enquiries, because holding someone's mobile number is not the same as holding their WhatsApp consent.

RCS sits closer to SMS, but it is not consent-free, and anyone telling you otherwise is selling something. Google's policy for business messaging requires consent before you solicit a customer, and it puts the opt-out machinery on you: you have to honour STOP and keep your own list of people who have asked you to stop, because Google does not maintain one for you. What you do not have to do is collect a second, channel-specific permission for an app the customer may not even use, or prove it against a registry.

That is the practical difference. A customer who consented to hear from you can be reached on RCS on the strength of that consent. The same customer cannot be reached on WhatsApp unless they separately opted in to WhatsApp messages from you by name. For a business sitting on a large consented customer list, that gap in addressable audience is usually wider than any difference in features.

The second difference: what happens when it fails

WhatsApp has no fallback. If the customer does not have WhatsApp, or never opted in, the message does not arrive and nothing else is tried. You find out through a non-delivery, after the fact.

RCS checks the handset at send time. When the rich version cannot be shown, a plain SMS version of the same message goes instead. In practice this means adding RCS cannot lower your reach: the floor is your existing SMS reach and the ceiling is higher for every customer whose handset supports it. It is the reason RCS is easier to adopt as an upgrade rather than a migration. There is more on that in RCS vs SMS.

The third difference: who sends you the bill

WhatsApp has two separate costs. There is a platform subscription for the software and support, and there is Meta's own per-message charge, which Meta bills you directly at its latest published India rate, priced by message category: marketing, utility and authentication are chargeable, while service replies inside an open 24-hour customer window are free. Nothing is added to Meta's rate by us.

RCS is simpler to reason about. It is billed per message through us, with the rate depending on your volume and message type, out of the same wallet as your SMS. There is no separate relationship with a platform owner and no category pricing to model.

Which works out cheaper depends entirely on your mix. A support-heavy business that mostly replies inside open windows pays Meta very little. A business running large one-way campaigns to a list that never opted in to WhatsApp cannot use WhatsApp for it at any price. Send us your actual monthly volumes and we will price both.

The India-specific limits, on both sides

Both channels throttle new senders, and both do it differently enough that the comparison is worth spelling out. Most write-ups skip it entirely.

WhatsApp caps the number of unique customers you can start conversations with in a rolling 24 hours. New business portfolios begin at 250 and climb through 2,000, 10,000, 100,000 and finally unlimited, on the strength of business verification, message quality and actually using at least half your current limit. Replies inside an open customer window do not count against it.

RCS in India works on a reputation tier instead, measured over a rolling 28 days, and Google's current documentation applies rules specific to this market. A promotional agent starts on the lowest tier and can reach up to a million unique users, but with only two initial messages per user in that 28-day period. The middle tier raises that to 25 million users and four initial messages, and the top tier to 300 million users and eight. As with WhatsApp, replies to a conversation the customer started are exempt. Two further India rules apply: promotional agents may only send between 7 AM and 10 PM, and multi-use agents are not offered in India, so each use case needs its own agent.

Read together, the two ladders point in opposite directions. RCS has by far the higher ceiling once your reputation is established, and WhatsApp's "unlimited" tier is reached by climbing from 250. But RCS is much stricter at the start: a hard cap of two initial messages per person per 28 days is a frequency limit WhatsApp has no equivalent of, and it rules out high-frequency promotional programmes until your agent has a track record.

Which should you use?

Or run both, which is what most do

These are not rival products competing for the same budget line. They cover different parts of the same customer base, and the overlap is smaller than it looks: the customers who opted in to WhatsApp are, almost by definition, your most engaged ones, and RCS is how you reach everyone else without dropping to plain text.

RCS, WhatsApp and SMS all run from the same SmsHorizon panel, the same API environment and the same wallet, with one set of reports across all three. That means you can route by job rather than by channel politics: OTPs and critical alerts on SMS for guaranteed reach, campaigns and rich announcements on RCS, ongoing conversations on WhatsApp. One integration, three channels, and no separate vendor for each.