Fundamentals · Smerio
RCS and SMS fallback, explained
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Compare the same message in RCS, SMS and MMS, then learn how to design a fallback path without sending duplicate notifications.
A little time to make.
Your pottery workshop is tomorrow at 10:30. Everything you need is waiting.
Media + action + suggested replies. The next step is part of the message.
North Studio: your pottery workshop is tomorrow at 10:30. View your booking or change the time:
north.example/bookingText + a link. Keep the essential information in a self-contained message.
North Studio: see you tomorrow at 10:30 for your pottery workshop.
north.example/bookingMedia + text. Attachment support and limits depend on the route and device.
Illustrative layouts. Actual appearance varies by messaging app. Photo: Tuan Nguyen / Unsplash.
One intent. Three ways to deliver it.
The examples above all do the same job: remind someone about a workshop. The channel changes how the message looks and what the recipient can do next.
| Format | What the recipient sees | What you design |
|---|---|---|
| SMS | Text, with an optional link | A complete, concise message |
| MMS | Media and text | An attachment and useful context |
| RCS | Branded messages, rich cards and supported actions | A conversation with clear next steps |
RCS is not limited to cards. You can send text, media, a standalone rich card or a carousel. A carousel groups several cards so a customer can browse options; suggested replies return a choice, while suggested actions can open a link or another supported device function. See Google’s rich-card guide.
Choose a route before choosing the format
RCS for Business reach depends on the recipient and the sender’s launch status. A capability check helps you determine whether the recipient is reachable and which features are supported.
Send the message and track its delivery events.
Send separately authored SMS or MMS content through an available route.
Fallback is an application or provider routing decision. It is not a promise that an RCS message automatically turns into an SMS. Different integrations implement it differently; Twilio’s documentation, for example, describes fallback configured through its Messaging Services.
Keep the fallback useful on its own
A card’s image and buttons will not survive as an SMS body. Preserve the business name, essential information and a usable link. For MMS, check the media constraints of the intended route.
A useful test: if the recipient sees only the fallback, can they still understand the message and complete the task?
A timeout is not proof of non-delivery
An RCS message may be queued while the device is offline. Sending an SMS immediately after a timeout can lead to both messages arriving later.
Track the RCS message state, define an expiry policy and handle late events. Where appropriate, use message revocation and inspect the result before attempting another channel. Google’s revocation guide explains this sequence.
| Record | Why it matters |
|---|---|
| Application event and message IDs | Connect attempts to the same customer event |
| Delivery state for each attempt | Distinguish accepted, delivered and failed |
| Fallback reason and time | Explain why another route was used |
| Late events | Detect and resolve possible duplicates |
Start with one conversation and test its normal path, unavailable-device path and delayed-delivery path. Then read how a test sender becomes a production sender.
Evaluating support costs? Compare WhatsApp service message pricing and RCS conversation billing using the complete customer journey, including fallback.
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