What is lexical?

Lexical is a language server for Elixir developers, think of it as a smart assistant that runs in the background of your code editor and helps you write code faster and catch mistakes earlier. It powers features like auto-completion, instant error checking, code formatting, and the ability to jump to a function's definition with a click. The key thing that makes Lexical different is how it's built. Instead of running all its code in one process, it actually starts two separate virtual machines that talk to each other. One runs Lexical itself, and the other runs your project code in isolation. This separation means Lexical can use any dependencies it needs without conflicting with your project's own dependencies, so you could even use Lexical to work on a project that Lexical itself depends on, without everything falling apart. It also means your project can use an older version of Elixir than Lexical does, which gives it flexibility to support older codebases while staying current. Because your code runs in its own isolated environment, Lexical can compile and check your code as you type, showing you errors immediately rather than forcing you to save first. The completions it offers are also smarter than you'd find in a typical language server. If you type alias MyModule.|, you'll only see module names, not function names. Inside a struct reference like %MyStruct.|, you'll only see modules that actually define structs. This context-aware approach means less noise and more relevant suggestions. The project is designed to be easy for other developers to contribute to, with clear separation between the language server and project code, consistent data models, and good test coverage. If you're an Elixir developer using an editor like VS Code or Neovim, installing Lexical gives you a modern development experience with many of the conveniences you'd expect from tools in other ecosystems.