5000 Flask-default TCP
Reference for TCP port 5000, commonly associated with Flask-default.
What it's for
Port 5000 is the traditional default port for Flask's built-in development server, one of the most popular Python web frameworks. Running flask run or app.run() without specifying a port will typically bind here, making it a familiar sight in Python web development tutorials and local projects.
Protocol basics
Like other dev-server default ports, there's no special protocol behavior tied to 5000 itself — it's plain HTTP, served by Flask's lightweight built-in development server (not intended for production use, which is why Flask docs recommend a proper WSGI server like Gunicorn behind a reverse proxy for anything beyond local development). Worth noting for macOS users specifically: port 5000 can conflict with the AirPlay Receiver service on modern macOS, a common source of "why won't my Flask app start" confusion that's unrelated to Flask itself.