Elm support is available through the Elm extension.

Setting up elm-language-server

Elm language server can be configured in your settings.json, e.g.:

  "lsp": {
    "elm-language-server": {
      "initialization_options": {
        "disableElmLSDiagnostics": true,
        "onlyUpdateDiagnosticsOnSave": false,
        "elmReviewDiagnostics": "warning"

elm-format, elm-review and elm need to be installed and made available in the environment or configured in the settings. See the full list of server settings here.