Fallback is the mechanism that makes an RCS-first programme safe to adopt before every customer is RCS-ready. It answers the objection every marketing team raises first, which is what happens to the people who cannot receive it. The answer is that they still get the message, in the format their phone supports, without anyone building a parallel campaign. It is also why what RCS messaging is can be answered without a reach caveat attached.
What happens at send time
The sequence is short and entirely invisible to both sides.
- You submit one message to one audience.
- The platform checks each destination number's capability, which is a live lookup rather than a stored guess, because capability changes as people change device, carrier, or settings.
- RCS-capable numbers receive the rich message: verified sender, images, rich cards, suggestion buttons.
- Everyone else receives a degraded but coherent version over SMS, or MMS where the message carries media.
- Delivery results come back tagged with the channel each message actually went out on.
There is a second kind of fallback worth knowing about. A number can be RCS-capable and the RCS delivery can still fail, for example if the handset never comes online within the message's time-to-live. A well-built platform retries and then falls the message over rather than dropping it.
What a rich message looks like when it degrades
This is where most of the design work is, and it is worth doing deliberately rather than leaving to a default. A rich card has an image, a headline, a description, and buttons. SMS has none of those things. So the fallback version has to carry the same intent in text: the core message survives, and any suggested action becomes a link.
The practical rule is to write the SMS version as a real message rather than as a stripped card. If the RCS message says "Your order shipped" with a Track button, the SMS should say "Your order shipped. Track it: [link]", not "Your order shipped." with the action silently gone. Check the fallback copy in preview before every campaign, because the failure mode is quiet: the message arrives, it just does nothing.
What fallback does to your bill
Billing follows actual delivery. RCS rates apply to messages delivered as RCS, and carrier SMS or MMS rates apply to the rest. This is exactly why the delivered-as breakdown matters: without it, you cannot reconcile an invoice, and you cannot tell whether your RCS share is growing. Our published rates are on the pricing page and every line of a bill is itemised on billing transparency.
MMS deserves a specific warning here. A media-carrying message that falls back becomes MMS, which is materially more expensive than SMS. A campaign with a large image and a low RCS-capable share can therefore cost more than expected, and the fix is usually to reconsider whether the image is doing enough work to justify carrying it to non-RCS recipients.
Why registration still matters
The SMS leg of a fallback rides a registered 10-digit number, so your 10DLC brand and campaign registration is what keeps that leg deliverable. Leading with RCS does not remove the requirement, it just means fewer messages take that path. 10DLC vs RCS sets out how the two layers fit together.
- Fallback is automatic and per recipient, driven by a capability check at send time rather than a stored list.
- One authored message covers both paths; rich content degrades to SMS, or to MMS when media is attached.
- Billing follows actual delivery, so a provider should report the delivered-as breakdown back to you.
- MMS fallback costs more than SMS, so heavy media on a low-RCS audience is the case to watch.
- SimplyRCS handles RCS to MMS to SMS fallback automatically on every send, through both the app and the API, at the same price.