Drawing 1 · Interactive
Who can you reach on the app, the carrier, or both?
Overlap
In both sets
8,10082% of everyone
Reachable both ways: here the choice is about consent, content and cost — WhatsApp for rich two-way messages, DLT-registered SMS as the fallback.
| Audience | Total | Only here |
|---|---|---|
| Reachable by SMS (carrier) | 9,600 | 1,500 |
| Reachable on WhatsApp (OTT) | 8,400 | 300 |
| In both | 8,100 | |
| Unique people | 9,900 |
Highlighting In both sets: 8,100. Reachable both ways: here the choice is about consent, content and cost — WhatsApp for rich two-way messages, DLT-registered SMS as the fallback.
What is OTT messaging?
OTT messaging — short for over-the-top — means chat services that run as apps over an internet connection, on top of a mobile operator's network rather than through its messaging systems. WhatsApp, Messenger and Instagram Direct are OTT services: the operator carries the data packets but does not see, route, price or control the messages. The term comes from telecoms and television, where over-the-top describes services delivered across someone else's network.
That changes who sets the rules. With SMS and RCS business messaging, operators and regulators decide how messages are routed, priced and filtered — in India through TRAI's DLT system of headers, content templates and consent. With OTT messaging the app owner decides. On WhatsApp, Meta defines business identity (a WhatsApp Business Account with an approved display name), what a business may send (approved templates outside the 24-hour customer service window), quality ratings and messaging limits, and the rate card: Meta has charged per delivered message by category since 1 July 2025.
The trade-offs follow. OTT apps offer rich media, interactive buttons, delivered and read statuses, end-to-end encrypted personal chats and business profiles, but reach only people who have installed the app and are online. SMS reaches any active mobile number, even a feature phone with no data, but carries plain text from a sender ID. RCS sits between them: rich features delivered by carriers inside the phone's default messages app where the handset and network support it. That is why most Indian businesses treat WhatsApp as the primary channel and keep DLT-registered SMS as the fallback.
Key takeaways
- OTT (over-the-top) messaging apps carry chats over mobile data or Wi-Fi, on top of the carrier's network rather than through its SMS system.
- The app owner sets identity, features, policy and pricing; for WhatsApp Business that is Meta, not the mobile operator.
- OTT apps offer rich media, buttons, read receipts and business profiles, but reach only people with the app and a data connection.
- SMS reaches every active number without data; RCS sits between the two, rich but carrier-delivered and dependent on the handset.
- Most Indian businesses run WhatsApp as the primary channel and keep DLT-registered SMS as the fallback.
Specifications
OTT messaging: key facts and limits
- OTT stands for
- Over-the-top: services run across someone else's network
- Transport
- Mobile data or Wi-Fi, not carrier SMS signalling
- Who sets the rules
- The app owner (Meta for WhatsApp)
- Reach
- People with the app installed and online
- WhatsApp business pricing
- Per delivered message by category since 1 July 2025
- Carrier counterparts
- SMS (any phone) and RCS (capable handsets)
Design intent
Why does OTT messaging matter?
Choosing a channel is really choosing whose rules you follow, how many customers you can reach and what each delivered message costs. A business that understands the OTT model plans for Meta's policies, template approvals and quality signals on WhatsApp — and separately for TRAI's DLT rules on SMS — instead of assuming one rulebook covers every channel it uses.
Operating sequence
How does OTT messaging work?
The customer installs the app
An OTT app registers the user's phone number once — WhatsApp verifies it with a code by SMS or call — then works over any data connection, Wi-Fi included.
The business connects to the app owner
Businesses reach WhatsApp through Meta's Cloud API, directly or through a partner, with a Meta business portfolio, a WhatsApp Business Account and a registered phone number.
Messages travel over the internet
Your server calls the API over HTTPS and the app owner's servers deliver to the device. The operator sees only data traffic, not messages.
The app owner enforces policy
Templates are reviewed, quality is rated and messaging limits apply per business portfolio; on WhatsApp, Meta charges per delivered message by category.
Carrier channels stay the fallback
For people who are not on the app or not online, the same message goes by SMS — DLT-registered in India — or by RCS where it is supported.
Example: One buyer list, two rulebooks
A Surat textile wholesaler messages 6,000 retail buyers. About 5,400 of their numbers are on WhatsApp, so new catalogues go as marketing templates with image carousels to buyers who opted in, at ₹0.94 per delivered message, and orders come back as replies inside the 24-hour window. The 600 buyers not reachable on WhatsApp — many of them feature-phone users — get a DLT-registered SMS with a whitelisted catalogue link. The team follows Meta's rules for the OTT channel and TRAI's for the carrier one, and tracks orders per channel to see what each costs.
Failure modes
Common mistakes with OTT messaging
Assuming everyone is on the app
Even in a high-WhatsApp market like India some customers are not on it, are offline or use feature phones. Check reachability and keep an SMS or voice fallback.
Applying carrier rules to OTT, or the reverse
DLT headers and templates do not apply to WhatsApp, and Meta's template approval does not make an SMS compliant. Plan each channel's compliance separately.
Treating business OTT as costless
Personal chats cost users only data, but business messages on WhatsApp are charged per delivered message by category. Budget for them like any other channel.
Ignoring platform risk
On an OTT channel the app owner can pause templates, hold back limits or restrict an account for policy or quality reasons. Watch quality ratings and follow the business messaging policy.
Recommended practice
Best practices for OTT messaging
- Collect channel-specific consent: WhatsApp opt-in for WhatsApp, DLT-recorded consent for promotional SMS.
- Use WhatsApp delivered statuses to trigger SMS fallback only when it is needed.
- Compare channels on cost per delivered and per converted message, not on list price.
- Keep the brand name consistent across the WhatsApp display name, SMS header and RCS agent.
OTT FAQs
What does OTT mean in messaging?+
Is WhatsApp an OTT service?+
What is the difference between OTT messaging and RCS?+
Do TRAI's DLT rules apply to OTT messaging?+
* Per-message rates for India, ex-GST: marketing, utility and authentication effective 1 July 2026; service messages ₹0.145 since 1 October 2026 (they were ₹0 until 30 September 2026). Volume commitments earn discounts — final rate is confirmed on your account; applicable GST extra. Rates for other countries differ (see the international rate table on /pricing).