iMessage is Apple’s proprietary messaging service for Apple devices only; RCS is the open, cross-platform standard that works between Android and iPhone. On an iPhone, messages to other Apple users use iMessage (blue bubbles); messages to Android, and business messages, use RCS or SMS. iMessage has always been end-to-end encrypted; cross-platform RCS gained default end-to-end encryption in May 2026 (iOS 26.5). For businesses, RCS is the cross-platform branded channel, since iMessage isn’t open to general A2P messaging.
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RCS vs iMessage, line by line.
Every dimension, both sides. Search to jump to what matters, hover a row to focus it.
Android + iPhone (cross-platform)
Apple devices only
Yes (GSMA)
No (Apple proprietary)
P2P E2EE since 2026; A2P processed
E2EE since launch
Yes, RBM, verified, interactive
Not a general A2P channel
Verified brand name, logo, checkmark
A personal Apple ID or phone number
SMS/MMS
SMS to non-Apple
Why a business cannot simply send iMessage
There is no open API for pushing marketing or notification traffic through iMessage, and there is unlikely to be one. Apple runs a separate, invitation-style program, Apple Messages for Business, which is built around customer-initiated support conversations rather than outbound campaigns, and which most brands are not admitted to. Anyone promising blue-bubble campaigns is describing something Apple does not offer. What did change is the other direction: since iOS 18, iPhones speak RCS, so the branded, interactive message you build once is delivered natively to Android and iPhone alike, in the Messages app the customer already uses, with nothing to install on either side.
What iOS 18 and iOS 26.5 actually changed
iOS 18 turned on RCS on iPhone, which is what made a single cross-platform rich campaign possible for the first time. iOS 26.5, in May 2026, added default end-to-end encryption to cross-platform RCS chats, built on GSMA Universal Profile 3.0 and the MLS protocol, closing the gap that had been the strongest argument for iMessage. Neither release turned iMessage into a business channel, and neither removes the need for verification: sending branded RCS still means registering a brand and an agent with Google and the carriers, which is the work SimplyRCS does for you. For a US audience split between iPhone and Android, that one verified agent now covers the whole list.
iMessage wins for Apple-to-Apple consumer chat and its long-standing encryption. RCS wins for reaching everyone, it’s the only rich channel that spans both ecosystems, and it’s how brands send verified, interactive business messages cross-platform.
- iMessage is Apple-only and consumer-focused; it is not a general business-messaging channel (Apple Messages for Business is a separate, limited program).
- Cross-platform RCS E2EE shipped by default (beta) in iOS 26.5 on May 11, 2026, built on GSMA Universal Profile 3.0 and the MLS protocol.
- Apple added RCS support in iOS 18, so one verified RCS agent reaches both iPhone and Android users.
- On iPhones where RCS is off or unsupported, SimplyRCS falls back to SMS or MMS so the message still arrives.
RCS vs iMessage, common questions.
RCS messaging vs iMessage: what does the difference mean for a business?
iMessage is closed to outbound business campaigns, so a brand cannot send through it. RCS messaging is the open standard that Android and, since iOS 18.1, iPhone use for business messages, so one verified RCS agent reaches customers on either platform and falls back to SMS where RCS is not switched on.
Is RCS the same as iMessage?
No. iMessage is Apple’s own service and only works between Apple devices. RCS is a carrier standard that runs in the native Messages app on Android and, since iOS 18, on iPhone too. One verified RCS campaign can reach customers on both, with no app to install.
Can a business send messages through iMessage?
Not for outbound campaigns. iMessage has no open business-messaging API, and Apple Messages for Business is a separate, limited program built around customer-initiated support conversations. RCS Business Messaging is built for outbound: a verified sender identity, rich cards, and tappable buttons delivered to the default inbox.
What happens on an iPhone that has not turned on RCS?
SimplyRCS falls back to SMS or MMS automatically, so the message still arrives. No customer is missed because of their device or settings.
Is RCS encrypted like iMessage?
Person-to-person RCS chats gained default end-to-end encryption in iOS 26.5, released in May 2026, built on GSMA Universal Profile 3.0 and the MLS protocol. iMessage has been end-to-end encrypted since launch. Business messaging on either channel is processed by the platform rather than end-to-end encrypted, which is what makes delivery and read reporting possible.
Do I need separate campaigns for iPhone and Android?
No. One verified RCS agent covers both. You build the message once and SimplyRCS delivers it as RCS wherever the handset supports it, and as SMS or MMS everywhere else.
Why do some messages still arrive as green bubbles?
Bubble color reflects the transport. An Apple-to-Apple chat uses iMessage and shows blue; anything else on an iPhone is RCS or SMS. Business messages are never iMessage, so the question that matters for a brand is whether the message arrives verified and interactive, which is what RCS provides.
Compare RCS with another channel.
Nine head-to-heads, including the one you are reading.