Use render with `respond_to`

You can use the render method to display content in a different format such as JSON or XML. This can be useful when working with APIs.

For example, to render a JSON response, you can add the following code to your controller action:

def show
  respond_to do |format|
    format.html # show.html.erb
    format.json { render :json => @post }

In this example, if the request is made in HTML format, the show.html.erb file will be rendered. But if the request is made in JSON format, the @post object will be converted to JSON and returned in the response.