There are multiple ways to send a mobile message today. iMessage, SMS, MMS, and RCS are just four channels that sit side by side, potentially within the same inbox. To the everyday user, the messaging experience may appear simple and seamless, but behind the scenes, things are a little more complex.
Each of these channels works differently, reaches different audiences and offers different benefits and challenges for businesses wanting to use them to communicate with customers.
Keep reading to explore iMessage, SMS, MMS, and RCS in detail, including their features, reach, and how they’re used, as we aim to unpick which channel is most commonly used today.
iMessage — Apple’s rich messaging closed ecosystem
iMessage is built into all iOS devices, including iPhones, iPads, Macs, Apple Watches and Apple Vision Pro. It only works fully within Apple’s ecosystem, and only Apple users can send iMessage-to-iMessage.
iMessages are exchanged using Wi-Fi or mobile data and are end-to-end encrypted (E2EE) by default, meaning they’re automatically secure at the highest level. Only the sender and recipient can read the content of iMessages, ensuring conversations are private and safe.
Rich features have always been part of the iMessage experience. Users can send high-resolution images and videos without compression and add emotion and personality to their conversations with emojis, stickers and tapback reactions. It’s also possible to edit iMessages, unsend them, schedule them in advance and see when the other person is typing a reply.
What happens when the recipient doesn’t have iMessage?
Until recently (late 2024), iMessages sent to Android users had to be sent as regular text messages, aka SMS or MMS. But now, messages can be sent using RCS — another rich messaging protocol, as long as the recipient’s phone supports it.
SMS — the birth of mobile messaging
SMS (Short Message Service) is the first iteration of mobile messaging. It launched in 1993 and was originally intended for customers to receive notifications from their mobile carrier. SMS evolved across cellular networks and devices, allowing person-to-person chat with messages of up to 160 characters.
SMS messages travel quickly to the nearest cell tower and onward to an SMS Centre (SMSC), a central network hub (a bit like a traffic controller). The SMSC routes text messages to the cell tower nearest the recipient, where they’re then broadcast to the recipient’s phone.
Because SMS is limited in character length and functionality, it’s great for quick alerts but not ideal for long messages — and it’s unusable for sending media. However, SMS is still used by most people with a mobile phone today for one reason or another because it’s very reliable and universally compatible. It works natively on all mobile phones, even non-smartphones.
For these reasons, SMS is popular among businesses seeking an accessible, near-instant way to reach customers. Consider two-factor authentication (2FA) PIN codes and one-time passwords (OTPs), as well as appointment reminders or delivery updates. These are short but important and time-sensitive communications. Businesses need to opt for the channel that’s most likely to deliver such messages — and SMS wins here because it works in areas with poor data connectivity and bypasses restrictions that you might get with internet-based messaging apps, like server outages or software glitches.
SMS security
SMS poses some security risks. There’s no E2EE, meaning the content of messages is readable as it travels across carrier networks. SMS also uses legacy infrastructure, specifically SS7 (Signalling System No. 7), which is a set of global telecoms protocols that providers use to route calls and texts. SS7, being an older system, can be exploited by attackers.
MMS — a visual upgrade to SMS text messaging
MMS (Multimedia Messaging Service) was developed in the early 2000s as an upgrade to SMS, allowing users to send various forms of media — photos, video, audio, GIFs and, on some networks, PDFs. It also allows for longer text-based messages of up to 1,600 characters and small group chats.
Like SMS, it utilises mobile carriers for transmission but also requires a data connection to upload and download media content to and from the mobile carrier’s messaging server.
Similar to SMS, MMS has limits. It typically allows files of less than 1 MB to be transmitted. In practice, this means that most media is heavily compressed and can appear blurry at the receiver’s end.
When MMS first came about, around the same time as camera phones, it was very popular, albeit more expensive than SMS. It almost had the ‘wow’ factor back then — imagine being able to capture a photo with your phone and send it to a friend on their own handset! Nowadays, photo sharing via mobile messaging has become the norm, with most people viewing MMS as outdated and preferring apps like WhatsApp, iMessage, or RCS for the rich features they offer.
Related reading: Learn more about the features and differences between MMS and RCS.
RCS — a rich, interactive modern text message experience
RCS (Rich Communication Services) was designed to become the next-generation version of SMS/MMS - bringing all the features of modern rich messaging right into the native texting app on mobile phones. Via RCS, users can send high-resolution images, videos, audio, GIFs, files, emojis, stickers and long text-based messages of up to 3,072 characters. Conversation indicators and large group chats are also key features.
Launched by the GSMA in 2008, RCS initially experienced a slow rollout due to fragmented carrier adoption, the high costs of new infrastructure, device and platform incompatibility and competition from apps like WhatsApp and iMessage.
RCS was used more widely in 2016 when Google incorporated it into its Android messaging app (Google Messages). But it really took off in late 2024 when Apple agreed to activate RCS on iPhones via its operating system release iOS 18. This enables RCS to work cross-platform, offering a much better texting experience for Android-iPhone messaging and vice versa.
RCS requires an internet connection for message transmission, like iMessage. RCS messages between Android users can use E2EE if both devices support RCS and have E2EE enabled. As of May 26, Apple began rolling out E2EE (in beta) to support cross-platform RCS chats between Android and iPhone devices.
One of the main benefits of RCS is that there’s no extra app for people to download to enjoy rich texting. It works invisibly in the background, falling back to SMS/MMS if the message should fail to deliver, which can happen if there’s a poor internet signal or the mobile phone doesn’t have RCS enabled.
Is RCS available on all phones?
RCS is now available on most modern smartphones — that’s the majority of Android phones and iPhones running iOS 18 or newer. However, RCS isn’t universally supported as yet because availability depends on network and device compatibility, and both the sender and recipient must have RCS enabled on their phones.
How iMessage, SMS, MMS and RCS are used in 2026
To answer which of these messaging channels are most commonly used today, we need to explore how they’re used and why. Below is a table comparing technical capability, accessibility, user behaviour, and market reach.
Protocol | iMessage | SMS | MMS | RCS |
Works on | Apple devices only (iPhones, Mac, Apple Watch, etc.) | All mobile phones, even basic ones | Most mobile phones, including basic ones that have a colour screen and support GPRS | All modern Android phones and iPhones running iOS 18 or newer |
Requires internet / mobile data | Yes | No | Requires 2.5G | Yes |
Content supported | Images, video, audio, GIFs, stickers, emojis, documents, files, text, link previews, tapbacks, screen effects, contact cards | Text only | Text, images, GIFs, short video clips, audio and some files (contact cards, PDFs, depending on file size) | Images, videos, audio, GIFs, files, documents, link previews, emoji reactions, *buttons, *suggested replies, *carousels, *rich cards (*business use only) |
Other key features | Group chats up to 32 people Typing indicators, read receipts Location sharing Apple Pay integration | Group chats for 10-20 people | Group chats up to 100 people Typing indicators, read receipts Location sharing | |
Security level | E2EE | No encryption | No encryption | E2EE for some RCS chats. TLS or no encryption on others |
Cross-platform reach | No | Yes | Yes | Yes |
Typical individual usage | Casual everyday texting, sharing media and location | Quick, informal text-based messages and check-ins | Sending media to someone who doesn’t use apps or have internet access | Casual everyday texting, sharing media and location |
Typical business usage | Customer service conversations, sales support, in-message payments | Time-sensitive notifications — 2FA PIN codes and OTPs, short one-way marketing blasts, reminders, order and delivery updates | One-way visual marketing to showcase products, coupons or digital tickets with QR codes | Interactive marketing with rich product cards, brand awareness, and customer service conversations |
Popularity / potential reach | 2.5 billion active Apple devices with iMessage capability Limited to Apple’s ecosystem / not universal | 8.5 billion mobile subscribers capable of sending and receiving SMS SMS business growth slowing, with global revenue forecast shrinking by 28% by 2029 | Remains part of the mobile messaging mix, but no evidence to directly show popularity today | 3.4 billion mobile subscribers can use RCS Fast-growing — RCS for Business mobile operator revenue predicted to achieve 225% growth by 2030 |
Message fallback status | Falls back to SMS/MMS | SMS is the fallback | No fallback | Falls back to SMS/MMS |
Main limitations | Locked into Apple’s ecosystem, inconsistent experience across platforms, and reliant on internet | Text-only messages, strict character limit, lack of security | Small media file size limits, compressed media, lack of security | Inconsistent security, not universally supported, reliant on internet, carriers and telecoms infrastructure |
Text messaging FAQs
Despite how often we use SMS and MMS, there are still some misunderstandings around them and whether they’re in fact the same thing. We answer some common questions below.
1. Do all text messaging systems use SMS?
Only MMS uses the same type of cellular messaging infrastructure as SMS. While SMS and MMS each operate over cellular networks, RCS and iMessage (plus instant messaging apps like WhatsApp, Signal and Messenger) use only WiFi or mobile data for delivery.
2. Is SMS outdated?
SMS is now seen as outdated as it relies on decades-old telecoms systems, is less secure than modern messaging channels, and lacks the rich media features most people expect today. SMS is still around and widely used because it’s universal, highly accessible, and doesn’t require an internet connection. If you need to make sure a message gets through, SMS is the most reliable option.
3. Is MMS the same as SMS?
MMS is different to SMS because it allows users to send low-resolution multimedia messages to any phone capable of receiving an image. SMS is limited to text-based messages of up to 160 characters. They are similar in that they’re both carrier-based text messaging protocols and use the native messaging app.
The most common messaging channel in 2026
All evidence suggests that SMS, despite its technical and security limitations and dated infrastructure, remains the dominant messaging channel today. Its reach hugely surpasses iMessage and RCS, with every mobile phone in existence today able to support it. For businesses, this reason alone is why they choose SMS for critical and time-sensitive communications.
Both RCS and iMessage have a large user base, but nowhere near the scale of SMS. iMessage is closed off to anyone without an Apple device; however, RCS usage is growing rapidly. MMS usage is difficult to measure, but we can confidently say that most people would prefer to use iMessage, RCS, or another OTT app to send media if they had the choice, given the low file-size limits of MMS.
So, while SMS is still the most wide-reaching messaging channel today, the reality is that there’s a place for all the others in a modern messaging mix. iMessage and RCS, in particular, offer great flexibility for rich conversations, proving popular with individuals and businesses alike.
