#ESSYS* is an online-based happening that unveils the underlying emotions in Twitter data. Built over the sonification system ESSYS, musical pieces are continuously generated and played online as an expression of Twitter’s most prominent emotions. The authors of each tweet become the conductors of this happening, devised as an audiovisual showcase, where we hear Twitter’s emotions, and we see the leading words that reflect this emotional dimension. The autonomous system is the performer in constant dialogue with each participant, in a unique event dependent on how the system itself interprets the tweets and their emotions, how it generates musical pieces, and how each audience member feeds the system and composes the happening’s narrative. The system will endlessly compose as long as tweets with the hashtag #essys-xcoax are shared, in an ever-changing, audiovisual event to expose the driving emotions of #ESSYS*.