Google Allo was the messaging app launched in 2016 that used machine learning to suggest replies.
Google introduced Allo at its I/O developer conference in May 2016 and released it in September of that year. The mobile app supported text conversations, stickers, image sharing, and an assistant that could appear inside chats.
One of its notable features was Smart Reply. By analyzing the conversation and an attached image, the app could offer short suggested responses, such as replies to a photograph. Allo also included an incognito mode with end-to-end encryption for selected conversations.
Allo is often mixed up with Google Duo, which launched alongside it as a video-calling app. Google discontinued Allo in March 2019, while Duo continued separately before later being merged with Google Meet. The short-lived app is therefore a historical Google messaging product, not a current service.