Did you mean to visit localhost:4200?

Did you mean to visit: http://localhost:4200/?

About Port 4200

Port 4200 is commonly used by:

Angular applications using Angular CLI
Ionic framework applications
NativeScript with Angular

Common Issues with Port 4200

"Port 4200 is already in use"

This error occurs when another application is already using port 4200. Solutions:

Find and close the application using port 4200
Use a different port:
- Angular CLI: ng serve --port 4201
- In angular.json: Set "port": 4201 in the serve options
On Windows, find and kill the process: netstat -ano | findstr :4200 then taskkill /PID [PID] /F
On Linux/Mac: lsof -i :4200 then kill -9 [PID]

"Cannot access localhost:4200 from other devices"

By default, Angular's development server only listens on localhost:

To make it accessible from other devices on your network: ng serve --host 0.0.0.0
Then access it using your computer's IP address: http://YOUR_IP:4200

"Changes not reflecting in the browser"

If your code changes aren't showing up:

Check if the Angular development server is running with hot reload enabled
Try clearing your browser cache
Restart the development server with ng serve
Check for errors in the terminal or browser console

Useful Resources

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