How to try the ty type checker

This guide shows you how to try out ty, a new static type checker and language server, in your project.

Prerequisites

To proceed, you’ll need uv.

Run ty from the command line

uvx ty check .

This checks all Python files recursively from the current directory.

Use the ty Language Server

Ty includes a Language Server Protocol (LSP) implementation compatible with modern editors.

VS Code and Cursor

Install the official ty extension from the Visual Studio Marketplace.

Other LSP-Compatible Editors

Install ty with uv install ty. Configure your editor to launch the ty server using its LSP support.

If you’re using nvim-lspconfig for Neovim, add this block:

lspconfig.ty_ls = {
  default_config = {
    cmd = { "ty", "lsp" },
    filetypes = { "python" },
    root_dir = lspconfig.util.root_pattern("pyproject.toml", ".git"),
  }
}
-- Optional: attach manually
lspconfig.ty_ls.setup{}

For Emacs, add the following to your init file:

(require 'lsp-mode)
(lsp-register-client
 (make-lsp-client
  :new-connection (lsp-stdio-connection '("ty" "lsp"))
  :major-modes '(python-mode)
  :server-id 'ty-lsp))
(add-hook 'python-mode-hook #'lsp)