Blog & Knowledge Base

Understanding mobile messaging technologies and group messages

Modern smartphones support several different messaging technologies that often coexist next to each other. While they may look similar to the end user, they differ significantly in how they work, how messages are delivered, and what features they make possible.

In this article, we will take a deeper look at the three major messaging technologies used on Android devices: SMS, MMS, and RCS. We will explain what they do, what they don’t do, how group communication actually works in each of them, and why DesktopSMS can only work with standard SMS.

Overview of mobile messaging technologies

Although users simply “send a message,” the underlying mechanisms differ:

• SMS – classic, simple, globally supported messaging delivered over carrier infrastructure.
• MMS – SMS extension for sending images, audio, and true group messages.
• RCS – modern IP-based messaging standard built into Google Messages, similar to WhatsApp.

SMS

SMS is the most basic and most compatible messaging technology. It works through the carrier network, requires no internet, and is supported by every mobile phone.

• ✔ Reliable and globally supported
• ✔ Works without internet — delivered through carrier infrastructure
• ✔ Accessible to third-party apps via stable Android API
• ✘ No typing indicators, read receipts, or reactions
• ✘ No true group messaging — multiple recipients get separate 1:1 messages
• ✘ 160-character limit per segment (messages are concatenated automatically)
• ✘ No image or file attachments

Because SMS does not support true group messages, sending to multiple contacts means sending multiple separate one-to-one messages. This is exactly how DesktopSMS works as well.

MMS

MMS was designed to extend SMS with multimedia content and real group chat capabilities. It uses the carrier network but requires mobile data to be active.

• ✔ Supports images, audio, and small files
• ✔ True group chats — replies are distributed to all participants by the carrier back-end
• ✘ Requires mobile data even when Wi-Fi is available
• ✘ Higher cost — some carriers still charge per MMS
• ✘ Slow delivery and poor media quality
• ✘ Not reliably supported by all carriers or countries
• ✘ No reliable public API for third-party apps on Android

RCS

RCS is the newest and most advanced messaging platform. It works over the internet and provides a feature set comparable to WhatsApp or iMessage — but requires both parties to have it enabled.

• ✔ Typing indicators, read receipts, and message reactions
• ✔ High-quality image and video sharing
• ✔ Real group chats with shared conversation history
• ✘ Requires Google Messages and an active internet connection
• ✘ Both sender and all recipients must have RCS enabled — falls back to SMS/MMS otherwise
• ✘ No public API available for third-party apps

Group messaging: SMS vs MMS vs RCS

How DesktopSMS fits into this

DesktopSMS is designed around classic SMS because SMS is the only universally supported and developer-accessible messaging technology on Android. MMS and RCS have fundamental limitations that prevent DesktopSMS from supporting them:

• ✘ RCS is proprietary — Google does not expose APIs for third-party apps
• ✘ MMS is highly carrier-specific — Android does not provide a reliable public API to send or manage MMS
• ✔ SMS is the only stable and officially supported option for apps that want to send messages on behalf of the user