Desktop GUI User Login System

Level: Real-World Project

Project Description

Today’s project is to build a real-world login system with a graphical user interface (GUI) using Python. This app will allow users to register and log in with a username and password, and after a successful login, they’ll be taken to a new screen that acts like a personal dashboard.

The login system will store user credentials in a local file using the JSON format. This means that the app will remember registered users even after you close it. It's a great way to simulate how basic authentication works in real-world desktop applications — no database or internet connection required.

Here’s what your app will do:

• Show a login screen where users can enter their username and password

• Let users register if they don’t already have an account

• Store login data in a file called users.json

• Allow users to press Enter in the password field to log in quickly

• Open a new dashboard window after successful login, with a welcome message

• Hide the login window when logged in, and show it again after logout

• Avoid unnecessary popups — everything happens seamlessly inside the app

Real Application Scenarios

This kind of login system is incredibly useful in many real-world situations, including:

• Local desktop apps that need user authentication (e.g., finance trackers, diary apps, task managers)

• Multi-user tools where different users can access their own data or dashboard

• Prototypes for apps that will later use real databases or APIs — perfect for testing login flows early

• Teaching tools for demonstrating authentication, state transitions, and data persistence

The GUI will be built using Tkinter, Python’s standard library for building desktop apps. You’ll learn how to handle button clicks, keyboard events, pop-up messages, and file I/O — all in one project.

Expected Output

When you run the app, you’ll see a login window like this:

• If the user enters correct credentials, the login window will disappear and a new dashboard window will open saying.
  

  

• If the credentials are incorrect, an error popup will appear.

  

  
  

• If the user clicks Register, a new account will be saved to users.json, and they can log in with it afterward.

💡 Hint

Don’t know where to start? This hint will show you how to begin.

𝌣 Solution

🔒 This solution is available to paid subscribers only.