Did you mean to visit localhost:3000?

Did you mean to visit: http://localhost:3000/?

About Port 3000

Port 3000 is commonly used by:

React applications created with Create React App
Node.js applications using Express.js
Ruby on Rails development server
Gatsby development server

Common Issues with Port 3000

"Port 3000 is already in use"

This error occurs when another application is already using port 3000. Solutions:

Find and close the application using port 3000
Use a different port by setting an environment variable:
- React: PORT=3001 npm start
- Express: Change the port in your code
On Windows, you can find and kill the process: netstat -ano | findstr :3000 then taskkill /PID [PID] /F

"Cannot connect to localhost:3000"

If your application is running but you can't connect:

Check if your application is actually running
Make sure you're not using HTTPS when the server is HTTP
Try using 127.0.0.1:3000 instead of localhost:3000
Check if a firewall is blocking the connection

Useful Resources

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