A small-scale test for now
Google is testing a new feature in its Messages app that lets you react to messages using emoji. First spotted by Reddit users in a thread that was picked up by Android Police, the feature reportedly lets you react to a message by long-pressing on it. Then, you can select from emoji including thumbs up, thumbs down, anger, and crying with laughter. The feature appears to only work over RCS, and is not available in SMS-only conversations.
Messages isn’t the first chat app to get emoji reactions, which are also available in Facebook Messenger, Twitter direct messages, and Apple’s iMessage. Similar to iMessage, if you’re phone doesn’t currently have the feature (because you’re not a part of the test, for example) you’ll receive a standalone message to tell you if someone has used an emoji to respond to one of your messages, rather than seeing the emoji appear next to the message itself. It sounds like a similar workaround to what iMessage uses for its green bubble users.
For now, Google appears to be testing the feature with a small number of users. It’s unclear, however, if running the latest beta version of the app is a prerequisite to see the emoji reactions or if it’s a service-side flag set by Google.