I've got tailwindcss ^2.2.19 when I setup my project. I notice that jit didn't work. The output app.css size is 4 MB. I had to add --jit to my watch command: npx : [ "tailwindcss" , "--input=css/app.css" , "--output=../priv/static/assets/app.css" , "--postcss" , "--watch" , "--jit" , cd : Path.expand( "../assets" , __DIR__) ],