LSP, or Language Server Protocol, is a programming architecture created by Microsoft that focuses on the presentation of code rather than the underlying semantic model. It allows for the development of tools that can work with multiple programming languages by finding common ground among them. LSP uses JSON for data transmission, which is fast enough for most languages, but the framing of messages using HTTP is not ideal. LSP also lacks a level-triggered state synchronization system, which would be more efficient for IDE features. Despite these drawbacks, LSP has been successful in moving towards a more standardized IDE support.
https://matklad.github.io/2023/10/12/lsp-could-have-been-better.html