Since the early days of the internet, researchers have been interested in the distinctive use of language in digital settings. One particular feature is the use of emoticons, sequences of punctuation marks that represent facial expressions and which have recently been replaced by emoji, little colourful pictographs. Despite their popularity, research on emoji is still in its infancy. The present paper contributes to the study of emoji by testing one of the findings identified in linguistic research on typographic emoticons, namely that they may function as punctuation marks in computer-mediated communication. A corpus of messages in Spanish sent through the smartphone application WhatsApp was retrieved and chats containing emoji were selected and analysed. Quantitative analysis showed that emoji were used similarly to final punctuation marks. Nevertheless, a discursive analytical approach to the corpus revealed that emoji and punctuation do not carry out the same functions.