This chapter reviews the historical contribution of Twitter before it was rebranded as X in July 2023. Twitter was an open platform for social sciences research, particularly political communication, a source of social data so prevalent in the early 21st century that researchers referred to this scholarship as ‘Twitter studies’. The chapter revisits the many Application Programming Interfaces that Twitter offered to developers and researchers, including the REST, Search, Streaming, Academic, and Compliance APIs in addition to databases of political communication the company curated and shared with the research community before its contentious acquisition by Elon Musk in late 2022. The chapter concludes with an assessment of the research approaches developed for ‘Twitter research’ and the extent to which they are transferable to the ‘post-API era’.
