Fundamentals · Smerio
RCS and SMS fallback, explained
A practical introduction to richer business messages and the second delivery path your integration needs.
What is RCS for Business?
RCS for Business lets an approved business sender exchange branded messages with people using supported messaging apps. It can include rich cards, suggested replies and actions, alongside text.
For a developer, the useful question is what the recipient can do next. A booking confirmation might include an action to view the reservation. A delivery update might offer a tracking link. A conversation might offer a few clear reply choices.
Business RCS support varies by market, carrier and device. Consumer RCS availability alone should not be treated as proof that a particular business sender can reach every user. Google’s platform overview explains how agents, messages and events fit together.
What does SMS fallback do?
Fallback gives the application another channel when RCS is unavailable or when a routing condition is met. An implementation might check recipient capability before sending and use delivery events and a timeout to decide what happens next.
It is another delivery attempt, not a guarantee that the recipient will receive or read the message. Both channels need observable outcomes.
A rich card is also not an SMS body. Write a useful plain-text version with the essential information and an appropriate link. Keep the business identity and purpose clear in both formats.
Avoid two messages for one event
A slow RCS delivery can complicate a fallback decision. If SMS has already been sent, a late RCS delivery may produce duplicates. The integration needs a defined timing policy, message state and handling for late events.
Google documents message revocation and checking delivery events before attempting fallback. Read the revocation guide alongside your provider’s routing rules.
What should a developer measure?
- Whether the RCS message was accepted and ultimately delivered.
- Why an SMS fallback was attempted, and its final result.
- The time between the application event and delivery.
- Duplicate attempts and late events.
- Billable units and actual cost on each channel.
A fallback percentage does not automatically equal the same percentage of the bill. Rates and billable units differ. Use your supplier’s actual terms when estimating costs.
Where Smerio fits
We’re building a simpler route from exploring RCS to integrating it into a product, with SMS fallback considered from the start. The first focus is sender onboarding, useful test experiences and clear integration behavior.
Smerio is currently in development. Tell us what you want to build, or read how testing differs from production.
What should we explain next? Send us your feedback.