Using Psalm's Language Server

Psalm now has built-in Language Server Compatibility support so you can run it in your favourite IDE.

It currently only supports diagnostics (i.e. finding errors and warnings), but more functionality is coming soon.

It works well in a variety of editors (listed alphabetically):


I got it working with eglot

This is the config I used:

(when (file-exists-p "vendor/bin/psalm-language-server")
    (require 'php-mode)
    (require 'eglot)
    (add-to-list 'eglot-server-programs '(php-mode . ("php" "vendor/bin/psalm-language-server")))
    (add-hook 'php-mode-hook 'eglot-ensure)
    (advice-add 'eglot-eldoc-function :around
                (lambda (oldfun)
                  (let ((help (help-at-pt-kbd-string)))
                    (if help (message "%s" help) (funcall oldfun)))))


I've got it working with this plugin.

Setup is done via a GUI.

When you install the plugin, you should see a "Language Server Protocol" section under the "Languages & Frameworks" tab.

In the "Server definitions" tab you should add a definition for Psalm:

In the "Timeouts" tab you can adjust the initialization timeout. This is important if you have a large project. You should set the "Init" value to the number of milliseconds you allow Psalm to scan your entire project and your project's dependencies.

Sublime Text

I use the excellent Sublime LSP plugin with the following config:

            "command": ["php", "vendor/bin/psalm-language-server"],
            "scopes": ["source.php", "embedding.php"],
            "syntaxes": ["Packages/PHP/PHP.sublime-syntax"],
            "languageId": "php"

Vim & Neovim


LSP support was recently added to ALE's master branch, but not yet in a tagged release.

Remember to specify Psalm as a PHP linter:

let g:ale_linters = { 'php': ['php', 'psalm'] }


I got it working with vim-lsp

This is the config I used (for Vim):

au User lsp_setup call lsp#register_server({
     \ 'name': 'psalm-language-server',
     \ 'cmd': {server_info->[expand('vendor/bin/psalm-language-server')]},
     \ 'whitelist': ['php'],
     \ })

VS Code

Get the Psalm plugin here (Requires VS Code 1.26+):