History

After 10+ years the Elixir language gained an official implementation of the Language Server Protocol (or LSP), Expert!

It started around 2014 when Jake Becker created ElixirLS. It gained prominent adoption, and later on gained a maintenance team after Becker moved on from the project.

The project was primarily lead by Łukasz Samson, who continued being a proper steward of the project, adding new features and fixing bugs with new Elixir and OTP releases.

Around 2022, both Mitch Hanberg and Steve Cohen independently decided they wanted to create a new LSP implementation for Elixir. Both had wanted to make drastic architecture changes that wouldn't really work with ElixirLS.

So, Next LS and Lexical were both born around 2023.

In 2024 the three maintainers partnered together and with the Elixir core team to focus efforts on a single official project, Expert! This marked the creation of the official Language Server Team, composed of Mitch, Łukasz, Steve, and Jonatan Kłosko.

Mitch gave a presentation during the initial combination period at CodeBeam America 2025.

Expert is an amalgamation of Next LS and Lexical, taking innovations and architecture from each. Supplemented with features neither supported from ElixirSense, the library that powers much of the ElixirLS.

You can find Expert on GitHub.