title: Why is my Flask Web App not Detecting Changes in Code
body: <p>My Flask Web App doesn't change when I change my html code for website templates. I have set the environment variable <code>FLASK_DEBUG</code> to 1. </p>
  
  <p>This is part of my Python code for application.py:</p>
  
  <pre><code>import os
  
  from flask import Flask, session, render_template, redirect
  from flask_session import Session
  from sqlalchemy import create_engine
  from sqlalchemy.orm import scoped_session, sessionmaker
  
  app = Flask(__name__)
  
  # Check for environment variable
  if not os.getenv("DATABASE_URL"):
      raise RuntimeError("DATABASE_URL is not set")
  
  # Configure session to use filesystem
  app.config["SESSION_PERMANENT"] = False
  app.config["SESSION_TYPE"] = "filesystem"
  Session(app)
  
  # Ensure templates are auto-reloaded
  app.config["TEMPLATES_AUTO_RELOAD"] = True
  </code></pre>