Language Servers Guide — coc.nvim Documentation

Supported features

Note: Capabilities vary between servers.

Register custom language servers

Configure user-defined language servers in the languageserver field of the configuration file. See :h coc-config-languageserver for common language server settings.

There are three types of language servers: module, executable, and socket.

module language servers run on Node.js and communicate over Node.js IPC.
executable language servers are launched with an executable command and communicate over stdio.
socket language servers run in a separate process and are typically used for debugging.

Each language server type has its own configuration schema.

Example configuration for a module language server:

jsonc snippet

1	"languageserver": {
2	"foo": {
3	"module": "/usr/local/lib/node_modules/foo/index.js",
4	"args": ["--node-ipc"],
5	"filetypes": ["foo"],
6	"trace.server": "verbose",
7	"rootPatterns": ["root.yml"],
8	// Used for debugging Node.js
9	// "execArgv": ["--nolazy", "--inspect-brk=6045"],
10	"initializationOptions": {
11	},
12	"settings": {
13	"validate": true
14	}
15	}
16	}

module and filetypes are required for a module language server.

Example configuration for an executable language server:

jsonc snippet

1	"languageserver": {
2	"bar": {
3	"command": "bar",
4	"args": ["--stdio"],
5	"filetypes": ["bar"],
6	"cwd": "./src",
7	"initializationOptions": {
8	},
9	"settings": {
10	}
11	}
12	}

command and filetypes are required for an executable language server.

Example configuration for a socket language server:

jsonc snippet

1	"languageserver": {
2	"socketserver": {
3	"host": "127.0.0.1",
4	"port": 9527
5	}
6	}

port is required for a socket service. Start the socket server before coc.nvim starts.

Install coc-json for completion and validation support.

Browse the language server catalog

The catalog contains practical configuration examples for more than 50 language servers. Use the language server catalog to search by language or server name, then return here for connection modes, feature support, and configuration rules.