RCS messaging has gained significant attention from businesses in recent years because it allows them to engage customers via the native text messaging inbox — with high-quality interactive campaigns that utilise rich media, quick replies, long-form text and more.

RCS has been cited across the internet for having high open rates and driving higher engagement and conversions than traditional SMS campaigns. Google, for instance, has published a case study showing that the beauty company Clarins achieved a 3x higher average engagement rate with RCS compared to rich SMS.

It’s fair to say that RCS sets high performance expectations, and as an omnichannel messaging provider, we’re excited about the opportunities it presents. What isn’t widely talked about, however, is whether RCS actually underperforms against such expectations. One of our clients recently experienced this while using RCS for Business, so we’ve delved deep into the campaign data to uncover why.

Below is a short case study outlining our client’s objectives, the results from their RCS for Business campaign, and why those results were underwhelming. We also explain why it’s vital to have SMS as a fallback option and why businesses should consider using both RCS and SMS together in their messaging mix.

Campaign background / the challenge

Our client operates in the logistics/delivery space and needs to send One-Time Passwords (OTPs) for customer account logins.

OTPs are critical, time-sensitive communications. They’re used to verify a user’s identity at a particular point in time, such as when logging in to their account. OTPs can only be used once and have an expiry — usually within a few minutes — so time is of the essence for delivery. If the user doesn’t receive their OTP or doesn’t enter it into their login screen in time, the verification process must be restarted, causing delays and frustration.

Because RCS is delivered to the native text messaging inbox, it’s believed to have comparable open rates to SMS — typically above 90%. RCS is also thought to upgrade the verification process as it provides a branded sender identity to build trust among users, plus one-tap verification instead of having to memorise a code from SMS, then toggle between apps to enter it.

RCS messaging also offers several other benefits that are important for urgent alerts:

  • RCS delivers messages over the internet using mobile data or WiFi, offering greater flexibility than SMS. The latter relies on complex telecoms routing, which can sometimes cause issues such as message filtering (where SMS messages may be delayed or blocked).

  • RCS has more detailed and trustworthy delivery reports — it’s easy to see when messages are delivered and seen.

  • Businesses appear in the native messaging app with full branding (logo, business description, contact details, and a verification badge), which helps build brand awareness as well as trust.

  • As RCS supports rich media and other interactive elements, OTP messages can include more detail if needed, better formatting, and CTA buttons to make them easier to understand and act on.

With all the above advantages in mind, our client decided to try RCS to send OTPs in Germany for almost two weeks to see whether it would improve their verification completion rate, operational efficiency and ROI. They were used to SMS, however, and decided to keep SMS as a fallback option in case some RCS messages failed to deliver.

Related reading: RCS vs SMS: What is the Difference?

The results: what early campaign data revealed

Insights from the campaign data were surprising and not particularly aligned with the hype we’ve seen about RCS across the industry. The delivery rate for OTPs sent via RCS was significantly lower than that for SMS. The delivery rate is a vital metric that underpins all others, impacting both engagement and conversions. Given that RCS operates in the same native messaging environment as SMS, it would be easy to assume delivery rates would be broadly comparable. In reality, however, RCS is more dependent on factors such as internet connectivity, device compatibility and user settings, which can limit its reach.

On average, only 65% of RCS OTP messages were successfully delivered. Occasionally, the open rates reached 78%. This meant that up to 35% of RCS OTP messages were not delivered. Fortunately, because the client used SMS as a fallback, messages that weren’t delivered via RCS were resent via SMS, which increased the overall campaign delivery rate.

Why did RCS not perform as expected?

During our analysis of the campaign, we found that in 93% of failed RCS messages, the recipient’s mobile handset didn’t support RCS. We also found that 4% of mobile operators weren’t registered for RCS. In 3% of undelivered messages, there was no obvious reason for failure; however, issues with internet connectivity or phone numbers may have been the cause. In the latter case, SMS delivery was affected too.

Smartphones and RCS support

Although RCS messaging is certainly becoming mainstream, it’s clear that many mobile phones in use today still don’t support RCS. This includes iPhones with operating systems older than iOS 18, Android devices with outdated native messaging apps, and basic cell phones designed only for making calls and sending SMS messages. Our data tells us this is the main reason RCS messages fail to deliver.

Why aren’t all operators supporting RCS?

Some mobile operators choose not to support or register for RCS because of infrastructure costs — for instance, it requires substantial upfront investment to deploy RCS servers for data-based messaging. They also need to integrate with other carriers, which presents technical challenges and requires ongoing coordination. Even if they use Google’s Jibe platform for RCS, they will need some level of supporting infrastructure and must ensure that RCS is enabled on users’ devices.

The case for SMS as a fallback option

RCS message delivery relies on specific conditions being met. These include device compatibility, network carrier and mobile operator support and an active internet connection. If any of these conditions aren’t met, an RCS message may go undelivered.

As per our recommendation, our client used SMS as a fallback when RCS was unavailable, so the majority of OTPs sent during the trial period were delivered one way or another. SMS is very reliable, especially for messaging at scale, for the following reasons:

  • SMS messages travel over cellular networks, not the internet, so texts can be received even in remote areas with a patchy signal.

  • SMS works on all mobile phones, even non-smartphones, making it a highly accessible, universal messaging channel.

For urgent communications such as OTPs, it’s vital to have SMS as a backup option. Because while RCS enhances the messaging experience and can drive engagement, SMS is still the best option for ensuring messages actually get delivered. Ultimately, a less engaging message is far better than one that doesn’t reach the user at all.

The potential of hybrid messaging: RCS with SMS

Our early campaign data suggest that SMS achieves a higher and more reliable delivery rate than RCS. However, RCS usage is steadily growing as more mobile phone users update to newer operating systems and as supporting carrier networks continue to expand. According to Juniper Research, RCS is set to have an active user base of 3.8 billion this year (2026), while Market Research Future suggests the RCS industry will exhibit a compound annual growth rate (CAGR) of 12.16% between 2025 and 2030.

We believe that using SMS and RCS together in a messaging campaign is the current best practice today because each channel has strengths that complement the other's weaknesses.

RCS, with its rich media capabilities, is better for engagement and more effective customer interactions. However, traditional SMS is accessible to all mobile phone users worldwide, providing universal reach and reliable delivery, with messages received over 90% of the time.

Using Messente, it’s possible to run a single messaging campaign that prioritises RCS and automatically uses SMS as a fallback. Our system handles device checks and routine decisions, resulting in fewer missed messages and better overall performance.

For more information on hybrid messaging strategies and the best way to leverage RCS right now, please get in touch.