One small note: It looks like the 'Mix standalone' runtime option was removed late last year. Instead, you can use `Mix.install/2` pointing to your project directory:

  Mix.install(
    [
      {:my_app, path: Path.join(__DIR__, ".."), env: :dev}
    ],
    config_path: :my_app,
    lockfile: :my_app
  )

(The above snippet assumes a notebook located within a `notebooks/` directory, as per the article.)

Alternatively, you can connect to a running instance, e.g. a Phoenix project:

  $ elixir --sname my-app --cookie cookie -S mix phx.server
  $ LIVEBOOK_DEFAULT_RUNTIME=attached:my-app:cookie livebook server