LSP4IJ

LSP4IJ is a free and open-source

• Language Server protocol (LSP) client compatible with all flavours of IntelliJ.
• Debug Adapter Protocol support with Debug Adapter Protocol Run/Debug configuration.

It allows you to integrate any language server that communicates with its client via stdio:

• by developing an IntelliJ plugin with LSP extension points:
  • com.redhat.devtools.lsp4ij.server extension point to define a language server.
  • com.redhat.devtools.lsp4ij.languageMapping to associate an IntelliJ language with a language server definition.
• by manually adding language server definitions, supporting custom server settings. This approach doesn't require developing a specific IntelliJ plugin.

LSP4IJ also provides:

• an LSP Consoles view to tracks LSP requests, responses and notifications in a console:

If you select the language server node, you can configure it the same way as in the Language Servers preferences page

and use the left toolbar to Apply or Reset the settings.

• a Language Servers preferences page to configure the LSP trace level, the debug port to use to debug language server:

You can find more documentation in:

• the developer guide, providing step-by-step instructions on how to integrate a language server in LSP4J in an external IntelliJ plugin.
• the User-defined language server documentation, explaining how to integrate a language server in LSP4J with few settings.
• the user guide, which explains how to use LSP console and Language Server preferences.
• the LSP Support overview, describing which LSP features are implemented, and how.