SMS, RBM & OTT: Comparing the Messaging Channels for 2025

The business messaging landscape is becoming increasingly diverse, with SMS, Rich Business Messaging (RBM), and Over-the-Top (OTT) channels all vying for attention. Each has its own strengths and limitations, making it vital for enterprises to understand how they compare across reach, features, and security.

User Base

SMS continues to dominate in sheer scale, with a projected 8.5 billion mobile subscribers worldwide able to receive messages. This makes it the most universal channel, accessible regardless of handset type or app usage.

RBM, by contrast, will reach 3.4 billion subscribers—a significant number but still less than half of SMS. OTT apps, such as WhatsApp, WeChat, and Messenger, collectively attract 4.6 billion users, but this audience is highly fragmented across platforms and regions.

Market Presence

SMS is unmatched in ubiquity: every mobile phone supports it. RBM’s presence is growing, particularly as operators roll out support, but only around 40% of subscribers globally will be able to receive it by 2025.

OTT apps present a more complex picture. While their global presence is undeniable, businesses face challenges in navigating a fragmented environment where success depends heavily on which platforms dominate in a given market.

High Reach Markets

In terms of penetration, SMS remains especially strong in the US, where brands make extensive use of A2P SMS for customer engagement. RBM is rapidly expanding here too, with forecasts suggesting 80% of US subscribers will be enabled by the end of 2025.

OTT channels, however, are often region-specific: China alone accounts for over 1 billion users of OTT messaging apps, while other regions are dominated by different providers such as WhatsApp in India and Latin America.

Metrics & Data

The kind of feedback businesses can expect from these channels also varies. SMS provides useful, though limited, insights such as delivery reports and click-through rates when linked with campaigns.

RBM offers a far richer analytics environment, with read receipts, delivery reports, and open rates available, making it closer to OTT experiences. OTT channels can provide even deeper engagement metrics, but these are app-specific and vary widely, limiting standardisation for global campaigns.

Security Features

Security remains a pressing concern for enterprises. SMS is vulnerable to risks such as spoofing and phishing, which continue to challenge regulators and businesses. RBM significantly improves on this with brand verification, encryption, and Google policy controls, giving businesses greater assurance.

OTT platforms also provide advanced protections, including brand verification and fraud detection, but again these differ between apps, adding another layer of complexity.

Key Takeaways

For businesses in 2025, no single messaging channel provides a perfect solution. SMS still wins on global reach and universality, making it indispensable for ensuring coverage. RBM represents a middle ground, blending scale with rich engagement features that appeal to brands looking for measurable interactions. OTT channels promise deep engagement and advanced tools but require navigating fragmented ecosystems and platform-specific rules.

The most effective strategy will not be about choosing one over the others, but about building multi-channel campaigns that leverage the strengths of each. By combining SMS for reach, RBM for rich functionality, and OTT for personalised engagement, businesses can deliver messaging strategies that are secure, measurable, and globally effective.

Source: A2P & Business Messaging Market 2025-2030

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