RCS (Rich Communication Services) is the upgrade to the plain text message. It lets brands send high-resolution images, carousels, buttons, and a verified sender profile inside the native messaging app. Since Apple added RCS support with iOS 18, it is no longer an Android-only story, and ecommerce brands running SMS programs need a plan for it.
The short version: RCS does not replace SMS today. It sits on top of it. Brands that treat RCS as an upgrade layer, with SMS as the fallback, get the creative upside without losing reach.
What is RCS?
RCS is a messaging protocol that adds app-like features to the default texting app on a phone. Think of it as SMS and MMS rolled into one, plus interactivity.
What RCS supports:
- High-resolution images, video, and GIFs
- Swipeable product carousels
- Tappable buttons and suggested replies
- Longer messages than the 160-character SMS limit
- A verified brand profile with your name and logo, vetted by carriers
RCS vs SMS vs MMS at a glance
| SMS | MMS | RCS | |
|---|---|---|---|
| Media | None | Images, short video (compressed) | High-res images, video, carousels |
| Interactivity | Links only | Links only | Buttons, suggested replies, carousels |
| Sender identity | Phone number or short code | Phone number or short code | Verified brand profile |
| Reach | Near universal | Near universal | Growing, device and carrier dependent |
| Fallback | n/a | SMS | SMS or MMS |
Why RCS matters for ecommerce
Three reasons this is worth your attention even before it is universal:
- Product discovery inside the message. A carousel lets a customer browse three to five products without leaving the thread. For launches, restocks, and BFCM, that is a bigger canvas than a text and a link.
- Trust. A verified sender with your logo and name reduces the "is this a scam?" hesitation that unknown numbers trigger. That matters more as consumers get warier of text spam.
- Better post-purchase experiences. Order confirmations and tracking updates with rich cards feel like part of your brand, not a generic alert.
What Apple's support changes (and what it does not)
Apple began supporting RCS with iOS 18, which put the protocol on both major mobile platforms. Since then, Apple has also rolled out end-to-end encryption for iPhone to Android RCS conversations (iOS 26.5, May 2026), though Apple describes it as beta and it depends on carrier and app support on both ends.
What has not changed: RCS delivery still depends on the device, the carrier, and user settings. Feature parity between iOS and Android is not complete. Plan for variation, not a uniform experience.
How RCS works with Klaviyo and Postscript
Both major ecommerce SMS platforms have built toward RCS with SMS fallback, so you do not have to choose one or the other.
- Klaviyo: Once a recipient is RCS-eligible, RCS becomes the preferred format, and Klaviyo falls back to SMS or MMS automatically when it is not. Klaviyo also reports RCS and fallback results together.
- Postscript: Supports RCS campaigns and flows, with SMS fallback so you keep reaching your full subscriber list.
Before you commit, confirm current availability and agent registration requirements with your platform rep, because these details have been changing quickly.
When to use RCS vs SMS
| Use case | Best fit | Why |
|---|---|---|
| Product launch or drop | RCS | Carousel and imagery do the selling |
| Cart abandonment | SMS first, test RCS | Speed and reach matter most; test rich cards for high-AOV carts |
| Order and shipping updates | RCS | Branded, tappable tracking card |
| Quick flash sale alert | SMS | Short, urgent, universal |
| VIP or loyalty offers | RCS | Verified sender builds trust, visuals feel premium |
| Winback | Test both | Creative refresh can lift a tired audience |
How to start without hurting your SMS program
- Check your list. Estimate what share of subscribers are on RCS-capable devices and carriers. That is your addressable RCS audience today.
- Start with one use case. A launch campaign or shipping update is a clean test.
- Keep SMS fallback on. Never let a customer miss a message because their device is not eligible.
- Hold out a control. Split RCS-eligible subscribers into RCS and standard SMS so you can measure incremental revenue, not just clicks.
- Watch compliance. Consent and opt-out rules still apply. RCS does not change TCPA obligations.
- Refresh creative. Rich messages need real assets: clean product imagery, short copy, one clear button.
What to measure
- Revenue per message (RCS vs SMS control)
- Click-through rate and button tap rate
- Opt-out rate
- Fallback rate (share of sends that did not deliver as RCS)
- Delivery rate by carrier
FAQ
Is RCS replacing SMS?
Not yet. SMS remains the universal baseline. RCS is an enhancement where devices and carriers support it.
Does RCS work on iPhone?
Yes, since iOS 18, with some feature differences from Android.
Do I need a separate list for RCS?
No. Your existing SMS subscribers receive RCS when eligible, with SMS fallback otherwise.
Is RCS more expensive?
Platform and carrier terms vary and are changing. See the current details in Klaviyo's RCS overview and Postscript's RCS update.
Can I track RCS performance?
Yes. Klaviyo and Postscript both report RCS and fallback performance.
How ATTN helps
ATTN builds SMS and RCS programs for ecommerce brands on Klaviyo and Postscript, from list growth and compliance to creative and testing. If you want a plan for adding RCS without disrupting what already works, talk to our retention team.
ATTN is a marketing agency, not a law firm. This article is general information, not legal advice. Laws and carrier rules on consent, messaging, and privacy change often and vary by state and situation, so consult your own attorney before making decisions about your program.