The Ruby LSP is an implementation of the language server protocol for Ruby, used to improve rich features in editors. It is a part of a wider goal to provide a state-of-the-art experience to Ruby developers using modern standards for cross-editor features, documentation and debugging.

Want to discuss Ruby developer experience? Consider joining the public Ruby DX Slack workspace.

The Ruby LSP features include

• Semantic highlighting
• Symbol search and code outline
• RuboCop errors and warnings (diagnostics)
• Format on save (with RuboCop or Syntax Tree)
• Format on type
• Debugging support
• Running and debugging tests through VS Code's UI
• Go to definition for classes, modules, constants and required files
• Showing documentaton on hover for classes, modules and constants
• Completion for classes, modules, constants and require paths
• Fuzzy search classes, modules and constants anywhere in the project and its dependencies (workspace symbol)

Adding method support for definition, completion, hover and workspace symbol is planned, but not yet completed.

See complete information about features here.

If you experience issues, please see the troubleshooting guide.

If using VS Code, all you have to do is install the Ruby LSP extension to get the extra features in the editor. Do not install the ruby-lsp gem manually.

See editors for community instructions on setting up the Ruby LSP.

The gem can be installed by doing

gem install ruby-lsp

and the language server can be launched running ruby-lsp (without bundle exec in order to properly hook into your project's dependencies).

See the documentation for more in-depth details about the supported features.

For creating rich themes for Ruby using the semantic highlighting information, see the semantic highlighting documentation.

By default, the Ruby LSP indexes all Ruby files defined in the current project and all of its dependencies, including default gems, except for

• Gems that only appear under the :development group
• All Ruby files under test/**/*.rb

By creating a .index.yml file, these configurations can be overridden and tuned. Note that indexing dependent behavior, such as definition, hover, completion or workspace symbol will be impacted by the configurations placed here.

# Exclude files based on a given pattern. Often used to exclude test files or fixtures
excluded_patterns:
  - "**/spec/**/*.rb"

# Include files based on a given pattern. Can be used to index Ruby files that use different extensions
included_patterns:
  - "**/bin/*"

# Exclude gems by name. If a gem is never referenced in the project's code and is only used as a tool, excluding it will
# speed up indexing and reduce the amount of results in features like definition or completion
excluded_gems:
  - rubocop
  - pathname

# Include gems by name. Normally used to include development gems that are excluded by default
included_gems:
  - prism

The Ruby LSP provides an addon system that allows other gems to enhance the base functionality with more editor features. This is the mechanism that powers addons like

• Ruby LSP Rails
• Ruby LSP RSpec
• Ruby LSP rubyfmt

Other community driven addons can be found in rubygems by searching for the ruby-lsp prefix.

For instructions on how to create addons, see the addons documentation.

• RubyConf 2022: Improving the development experience with language servers (Vinicius Stock)
• Remote Ruby: Ruby Language Server with Vinicius Stock
• RubyKaigi 2023: Code indexing - How language servers understand our code (Vinicius Stock)

Bug reports and pull requests are welcome on GitHub at https://github.com/Shopify/ruby-lsp. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

If you wish to contribute, see CONTRIBUTING for development instructions and check out our pinned roadmap issue for a list of tasks to get started.

The gem is available as open source under the terms of the MIT License.