IDE: neovim

In addition to standard vim support, Neovim's built-in support of language server protocol enables native use of Standard's --lsp server mode.

A configuration like the following could be used to set it up (borrows from @will's comment here):

vim.opt.signcolumn = "yes" -- otherwise it bounces in and out, not strictly needed though
vim.api.nvim_create_autocmd("FileType", {
  pattern = "ruby",
  group = vim.api.nvim_create_augroup("RubyLSP", { clear = true }), -- also this is not /needed/ but it's good practice 
  callback = function()
    vim.lsp.start {
      name = "standard",
      cmd = { "~/.rbenv/shims/standardrb", "--lsp" },
    }
  end,
})

This will provide inline feedback like the following:

nvim-lspconfig with Ruby LSP

To set standard as the linter and formatter for Ruby files, you can use the init_options key when setting up Ruby LSP:

local lspconfig = require('lspconfig')
lspconfig.ruby_lsp.setup({
  init_options = {
    formatter = 'standard',
    linters = { 'standard' },
  },
})