RCS Explained: The Upgrade That Is Replacing SMS

SMS dates from the early 1990s. It handles short plain text and, in practice, little else: images are compressed, group chats are unreliable and there are no read receipts. Rich Communication Services (RCS) is the industry's answer, a standard that gives the default messaging app the features of WhatsApp or iMessage. This article explains what RCS adds, how it differs from SMS and MMS, where it works today and what to watch out for.

What RCS adds

• Typing indicators and read receipts.
• High-resolution photos and videos instead of compressed MMS.
• Better group chats, with names and the ability to add or remove people.
• Messaging over Wi-Fi or mobile data rather than the SMS channel.
• Longer messages with no 160-character limit.
• Rich cards and buttons from businesses, such as boarding passes or delivery updates.

SMS, MMS and RCS compared

• Content

  SMS

  Short plain text

  MMS

  Compressed pictures and short video

  RCS

  Text, full-quality media, files, rich cards

• Needs data

  SMS

  No

  MMS

  Yes (carrier)

  RCS

  Yes (Wi-Fi or mobile data)

• Read receipts

  SMS

  No

  MMS

  No

  RCS

  Yes

• Works with any phone

  SMS

  Yes

  MMS

  Mostly

  RCS

  Only when both sides support it

A brief history

RCS was defined by the GSM Association in the late 2000s but was held back because each carrier implemented it differently. The turning point was the RCS Universal Profile, a common specification first published in 2016 and then adopted by carriers and by Google, which made RCS widely available on Android through Google Messages from 2019 onwards. Apple added RCS support to the iPhone with iOS 18, so messages between recent iPhones and Android phones can use RCS instead of falling back to SMS.

Who supports it

Most major carriers and Android manufacturers support RCS, and Google Messages offers it by default in many countries. Availability depends on your phone, your messaging app, your carrier and your country. When RCS is not available at either end, the message is sent as an ordinary SMS or MMS, so you never lose the ability to reach someone.

Security

RCS is not automatically end-to-end encrypted. The GSMA has added end-to-end encryption to the specification, and it is rolling out in specific apps and versions, so look for the lock indicator in your messaging app. Never send passwords or codes by any text channel. As with SMS, be careful with links from unknown senders: spam and phishing messages exist on RCS too, although carriers and apps filter them.

RCS and SMS still coexist

You will keep using SMS for many years, because it works with every phone. That is why tools like browser SMS still matter, and why it helps to understand SMS limits (see message length and delivery). To switch RCS on, follow our guide to enabling RCS in Google Messages, and read how other technology is changing mobile networks in 5G and GSM networks.

RCS for businesses

Companies can send rich messages with logos, buttons and carousels, for example a boarding pass, a delivery update with a map or a payment reminder. The messages come from a verified sender, which makes it easier to trust them than an unknown number. For users this is convenient, but you should still treat unexpected messages with care and never enter passwords from a link.