The Haskell Language Server (HLS) has shown how powerful the wealth of compile time information is that Haskell brings combined with instant feedback. For many, it is now a standard component of their development workflow. The HLS runs a complex, finely tuned machinery that handles large amounts of data about files, expressions, types and more, syncing it with the editor and continuously providing relevant information that can be displayed to the user.In this episode, Roman Cheplyaka talks to Zubin Duggal who contributed to HLS for years, personally, through various Summer of Code projects and recently as a Tweag Open Source Fellow. He explains how HLS emerged from various predecessors. the role the Language Server Protocol played in reducing the implementation efforts and then dives deep into the inner workings of this tool.If you want to understand what is happening when your editor shows information about your code, or if you want to get involved yourself to contribute to HLS or similar tools this episode is for you! Special Guest: Zubin Duggal.