from flask import Flask from flask_assets import Environment, Bundle app = Flask(__name__) assets = Environment(app) css_bundle = Bundle('styles/main.css', filters='cssmin', output='gen/packed.css') js_bundle = Bundle('js/main.js', filters='jsmin', output='gen/packed.js') assets.register('css_all', css_bundle) assets.register('js_all', js_bundle) {% assets "css_all" %} <link rel="stylesheet" type="text/css" href="{{ ASSET_URL }}"> {% endassets %} {% assets "js_all" %} <script type="text/javascript" src="{{ ASSET_URL }}"></script> {% endassets %}