What is RCS Chat? The Technical Definition
RCS stands for Rich Communication Services. It's an IP-based messaging protocol – meaning messages travel over your data connection (WiFi or mobile), not over the old SMS signaling network.
The technical difference sounds abstract but has concrete implications:
| Feature | SMS | MMS | RCS |
|---|---|---|---|
| Maximum file size | Text only (160 characters) | approx. 300 KB | Up to 100 MB |
| Media quality | – | Heavily compressed | HD quality |
| Read receipts | No | No | Yes |
| Typing indicator | No | No | Yes |
| Group chats | Very limited | Limited | Fully functional |
| Interactive buttons | No | No | Yes (Quick Replies, Suggested Actions) |
| App required | No | No | No |
The 100 MB file size isn't a typo. Compared to the 300 KB limit of MMS (which is often even less in practice), that's a factor of over 300x. You can send a complete product video in HD – directly to your customer's default messaging app.
RCS on iPhone: What Apple Users Need to Know
The big question for every marketer for years was: "When is RCS coming to iPhone?" The answer since late 2024: It's here.
With iOS 18, Apple integrated RCS into the default Messages app. As Apple confirms in their support documents, the iPhone uses the industry standard "RCS Universal Profile." This means: iPhones and Android devices can now exchange high-resolution images and videos, see typing indicators, and receive read receipts.
What doesn't change: RCS messages still appear as green bubbles.
This isn't a bug – it's intentional. Apple reserves blue bubbles for iMessage – their proprietary system for iPhone-to-iPhone communication. RCS is the fallback for everything else, and Apple makes this difference visually clear.
For your marketing strategy, this means: Don't expect your RCS campaigns to look like iMessage on iPhones. The features are (almost) identical, the appearance is not. But this shouldn't influence your decision – green bubbles with HD video and purchase buttons beat pixelated MMS every time.
iOS 26 and the Encryption Question
With iOS 26 (expected fall 2026), Apple is implementing MLS encryption (Messaging Layer Security) from Universal Profile 3.0. More on this in the technical deep dive below – but upfront: This primarily affects private chats between users, not Business Messaging.
RCS Business Messaging: The Marketing Tool
Now it gets concrete. RCS Business Messaging (RBM) is the channel through which businesses communicate with customers. And it offers significantly more than SMS ever could.
Verified Senders: The End of Smishing
When you use RBM as a business, your company name, logo, and verification checkmark appear in the message. The recipient immediately sees: This really is DHL, not a phishing attempt posing as DHL.
In times when SMS phishing (smishing) is a billion-dollar business for criminals, this is more than a nice feature. It's the reason recipients actually open your messages instead of reflexively deleting them.
Rich Cards: Product Presentation Directly in Chat
A Rich Card combines image, text, and call-to-action button in a compact unit. Think of a product card from your online shop – just in messaging format.
Pro tip for iOS compatibility: Text length on Rich Cards should not exceed 144 characters. Longer text gets cut off on iPhones. Android shows more, but if you want to serve both platforms (and you do), stick to 144.
Carousels: Multiple Products to Browse
With carousels, you display multiple Rich Cards in one message. Customers can browse and select a product directly from the chat.
Important: The display differs between platforms. On Android, carousels are swiped horizontally. On iOS, they're sometimes displayed as a vertical stack. Test your campaigns on both systems before going live.
Quick Replies vs. Suggested Actions: The Difference Few People Know
This is where expertise separates from superficial knowledge. RCS offers two types of interactive elements that are often confused:
Quick Replies are predefined text responses. The customer taps a button, and text is sent – such as "Yes, I want to order" or "No thanks." This is practical for surveys, confirmations, or simple decisions.
Suggested Actions are more powerful. They trigger native functions on the smartphone:
- "Save appointment" opens the calendar with a pre-filled entry
- "Show route" opens Google Maps or Apple Maps
- "Call now" initiates a phone call
- "Visit website" opens the browser
The difference: Quick Replies keep the conversation in the chat. Suggested Actions lead the user to an action outside the chat – and that's exactly what makes them so valuable for conversion.
An example: After an order confirmation, you send an RCS message with the Suggested Action "Track delivery." One tap, and the customer is in tracking – no copying URLs, no switching apps. That's the difference between "well informed" and "delighted."
What E-Commerce Companies Specifically Use RBM For
- Order confirmations with product image, tracking button, and estimated delivery date
- Cart abandonment campaigns with product carousel of left-behind items
- Flash sales with Rich Card and "Buy now" button (including deep link to checkout)
- Appointment confirmations with Suggested Action for calendar entry
- Support automation with Quick Replies for common questions
The advantage over email: Open rates of over 90% aren't the exception with RCS – they're the rule. Email struggles for 20-25% – when it goes well.
And unlike WhatsApp: No app installation required. The customer has a smartphone? Then RCS reaches them. How you orchestrate automated customer communication across different channels is a question of your tech stack. RCS integrates via APIs into existing systems – similar to what you might know from chatbot APIs.
Technical Deep Dive: Encryption and Standards
When compliance managers or IT leaders ask questions, you need precise answers. Here they are.
Universal Profile 3.0: The New Security Standard
The Universal Profile is the technical specification that defines how RCS works. The GSMA (the global mobile communications association) manages this standard.
Version 3.0, released in March 2025, brought a crucial innovation. According to GSMA, Universal Profile 3.0 defines the requirements for end-to-end encryption based on the Messaging Layer Security (MLS) protocol. This enables interoperable security between different providers – including between Google Messages on Android and the Messages app on iPhone.
P2P vs. RBM: Why the Encryption Discussion Needs Nuance
Here's the point many articles miss: The E2E encryption from UP 3.0 primarily applies to P2P communication – private chats between two users.
With RCS Business Messaging (RBM), the situation is different. Businesses need to be able to process messages: CRM integration, spam filters, compliance archiving, chatbot integration. End-to-end encryption would make this impossible – because then no one except the recipient could read the message, not even the sender's systems.
That's why RBM uses transport encryption (TLS) between systems and Verified Sender as the primary security feature. The message is protected in transit, and the recipient knows it really comes from you. This is a different security model than private chats – but the right one for business communication.
When a compliance manager asks "Is RCS encrypted?", the correct answer is: "P2P chats yes (E2EE via MLS), Business Messaging uses transport encryption plus sender verification."
Universal Profile 3.1
Version 3.1 (late 2025) adds:
- Improved audio codecs for voice messages
- Support for satellite connectivity
- Optimizations for weak network connections
For marketing purposes, 3.1 is less relevant – it addresses edge cases of user communication.
Carrier Support: Who Supports What?
Germany
According to iBASIS/Mobilesquared, over 55 million people in Germany were already RCS-enabled in 2025 – including approximately 11 million iPhone users. For 2026, these numbers are higher as iOS 18 now runs on more devices.
The carriers at a glance:
- Telekom: Full RCS support (Android + iOS)
- Vodafone: Full RCS support (Android + iOS)
- O2/Telefónica: Full RCS support (Android + iOS)
- 1&1: Limited. In their own 5G network (not Telefónica roaming), there were delays with iOS support. Android works. Users with 1&1 SIM in the 5G network and iPhone may rely on SMS fallback.
Austria
- A1, Magenta, Drei: RCS support available
Switzerland
- Swisscom, Sunrise, Salt: RCS support available
United States
- Verizon, AT&T, T-Mobile: Full RCS support (Android + iOS)
United Kingdom
- EE, Vodafone UK, Three, O2 UK: RCS support available
The rule of thumb: With the big three carriers per country, RCS works reliably. With MVNOs (discounters that rent networks), there may be gaps.
RCS vs. WhatsApp: An Honest Assessment
The question "RCS or WhatsApp?" is the wrong one. The right question is: "Which channel for which purpose?"
RCS strengths:
- Reaches everyone with a smartphone – no app installation, no account
- Verified senders as a strong trust signal
- Suggested Actions for native smartphone functions
- Deeper operating system integration
WhatsApp strengths:
- Established usage habits (90%+ market penetration in DACH, high globally)
- Consistent display across all devices
- Mature Business API with large ecosystem
- End-to-end encryption also for business
What we see with our customers: The combination performs better than either channel alone. WhatsApp for active conversations with existing customers who already use the channel. RCS as universal fallback and for customers who don't have WhatsApp (or reject it for business communication).
More on how WhatsApp Marketing works and where it complements RCS can be found in our guide.
Real-World Examples: What Messaging Strategy Looks Like
What does this look like in reality? Our customers show what's possible with structured messaging communication.
BEMS Home automated customer service via WhatsApp. The result: Faster response times, fewer tickets, happier customers. The same logic works with RCS – verified messages, quick-reply buttons for common questions, automatic escalation to humans for complex issues.
Farbenlöwe faced the problem that high inquiry volume overwhelmed support. With automated flows, standard questions are now answered immediately. Conversion-relevant inquiries land with real humans – with full context from the previous conversation.
The principle: Messaging channels work best when you don't treat them like email. It's about conversation, not one-way communication.
Setting Up RCS for Your Business
For end users, RCS is automatically active in most cases. Google Messages on Android, Messages app on iOS – as soon as your carrier supports RCS, it works.
For businesses, the process looks like this:
- Choose an RBM provider (like Chatarmin) that acts as the interface between your systems and carrier networks
- Complete business verification with Google (Google is currently the largest RBM hub)
- Submit brand assets: Logo, company name, verification details
- API integration into your CRM, marketing automation, or support system
- Testing on different devices and carriers
The process typically takes 2-4 weeks – depending on how quickly verification goes through and how complex your integration is.
Conclusion: The Right Time Is Now
2024 was the year Apple adopted RCS. 2025 brought the technical standards for secure communication. 2026 is the year businesses should seriously integrate RCS into their channel strategy.
The numbers speak for themselves: Over 55 million RCS-enabled users in Germany alone. Features that surpass SMS by light-years. A security model that fights phishing instead of enabling it.
Those who start now are building a channel while the competition is still deliberating. Those who wait will have to catch up later – and pay the price in missed conversions.
Frequently Asked Questions About RCS Chat
What is the difference between SMS and RCS?
SMS is limited to 160 characters of plain text and runs over the old mobile signaling network. RCS uses data connections, supports files up to 100 MB, HD media, read receipts, typing indicators, and interactive buttons. In short: RCS is SMS with the features of a modern messenger.
Does RCS Chat cost money for the recipient?
No. For end users, RCS is free – it only consumes data volume like any other internet application. Costs only arise for businesses using RCS Business Messaging through a provider.
Why are RCS messages green on iPhone?
Apple reserves blue bubbles for iMessage (iPhone-to-iPhone). As Apple confirms in their support documents, RCS messages appear as green text bubbles. This is intentional – Apple visually differentiates between its own service and the open standard.
Is RCS Chat secure and encrypted?
It depends. Private chats (P2P) between users are protected by Universal Profile 3.0 with end-to-end encryption via MLS. Business Messaging (RBM) uses transport encryption (TLS) and sender verification – E2EE isn't possible there since businesses need to process messages.
Does RCS work without internet?
No. RCS requires an active data connection (WiFi or mobile). Without internet, the message is automatically delivered as SMS – provided the sender has enabled this fallback option.
What are "Suggested Actions" in RCS?
Suggested Actions are interactive buttons that trigger native smartphone functions. A tap on "Save appointment" opens the calendar, "Show route" launches the maps app, "Call now" initiates a call. They differ from Quick Replies, which only send predefined text responses.
Do I need a separate app for RCS?
No. RCS is integrated into the default messaging app – Google Messages on Android, Messages on iPhone (from iOS 18). No installation, no account, no registration.
How large can files be with RCS?
RCS supports files up to 100 MB – compared to approximately 300 KB with MMS. This enables HD videos, high-resolution product images, and comprehensive documents directly in the chat.
Does RCS work in group chats between iPhone and Android?
Yes. With iOS 18 and Universal Profile 3.0, RCS group chats work cross-platform. All participants see read receipts, typing indicators, and can share HD media. Requirement: All participants have RCS-enabled devices and carriers.
How do I disable RCS Chat?
On Android (Google Messages): Settings → Chat features → Disable "Chat features." On iPhone: Settings → Apps → Messages → Disable "RCS Messaging." After deactivation, all messages are sent as SMS/MMS.
Want to test RCS for your business? Book your demo with Chatarmin now – we'll show you how to integrate RCS into your messaging strategy.
