Coc.nvim language servers

COC exposes language servers to vim, you'll need them to perform completion etc.

You can have multiple language-servers running at once on the same language/file (ex: ruby solargraph+sorbet).

Language Servers

Extensions

Language Servers may have a wrapper built for COC. These are called extensions.

You may install them dynamically with :CocInstall coc-python
and sometimes automatically like Plug 'neoclide/coc-tsserver', {'do': 'yarn install --frozen-lockfile'}.

python
unmaintained	coc-python
active	coc-pyright
sh, bash
active	coc-sh
ruby
active, ruby/rails	coc-solargraph
graphql
active	coc-graphql

Custom

Some programs may be able to function as an LSP, and can be registered to do so.
see https://github.com/neoclide/coc.nvim/wiki/Language-servers#register-custom-language-servers

{
   "languageserver": {
      "sorbet": {
        "command": "srb",
        "args": ["tc", "--lsp"],
        "filetypes": ["ruby"]
      }
   }
}

sorbet

// ~/.config/nvim/coc-settings.json
{
   "languageserver": {
      "sorbet": {
        "command": "bundle",
        "args": ["exec", "srb", "tc", "--lsp"],
        "filetypes": ["ruby"]
      }
   }
}