Remember me functionality in Flask

Introduction

The "Remember me" feature helps users stay logged in even after closing the browser. It makes returning to a website easier without typing the password again.

When you want users to stay logged in on their personal devices.

For websites where frequent login is annoying, like social media or forums.

When you want to improve user experience by reducing login steps.

For apps that need to remember user preferences securely.

When you want to balance convenience with security by setting session duration.

Syntax

Flask

login_user(user, remember=True)

login_user is a Flask-Login function to log in a user.

The remember=True argument tells Flask to keep the user logged in across browser sessions.

Examples

This logs in the user but the login ends when the browser closes.

Flask

login_user(user)
# Logs in user for current session only

This keeps the user logged in even after closing the browser.

Flask

login_user(user, remember=True)
# Logs in user and remembers across sessions

Use this to log out and remove the remembered login.

Flask

logout_user()
# Logs out the user and clears the session

Sample Program

This Flask app lets users log in with a username and choose "Remember me". If checked, the user stays logged in after closing the browser. The protected page shows a greeting. Logout ends the session.

Flask

from flask import Flask, render_template_string, request, redirect, url_for
from flask_login import LoginManager, UserMixin, login_user, login_required, logout_user, current_user

app = Flask(__name__)
app.secret_key = 'secret-key'

login_manager = LoginManager()
login_manager.init_app(app)

# Simple user class
class User(UserMixin):
    def __init__(self, id):
        self.id = id

# User loader callback
@login_manager.user_loader
def load_user(user_id):
    return User(user_id)

@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        user = User(request.form['username'])
        remember = 'remember' in request.form
        login_user(user, remember=remember)
        return redirect(url_for('protected'))
    return render_template_string('''
        <form method="post">
            Username: <input type="text" name="username" required><br>
            Remember me: <input type="checkbox" name="remember"><br>
            <input type="submit" value="Login">
        </form>
    ''')

@app.route('/protected')
@login_required
def protected():
    return f'Hello, {current_user.id}! You are logged in.'

@app.route('/logout')
@login_required
def logout():
    logout_user()
    return 'You have been logged out.'

if __name__ == '__main__':
    app.run(debug=False)

Important Notes

Remember me uses cookies to keep users logged in securely.

Do not use "Remember me" on public or shared computers for security reasons.

Flask-Login handles the cookie creation and verification automatically.

Summary

"Remember me" keeps users logged in across browser sessions using cookies.

Use login_user(user, remember=True) to enable this feature.

Always provide a logout option to clear remembered sessions.