Port 3000 — Next.js / development HTTP
The Next.js CLI defaults to port 3000. Other development servers may use it too, but Node.js and React themselves do not impose a universal listener port.
Registry assignments, software defaults and local listeners are different things. A port number alone does not identify or secure a service.
Configuration and troubleshooting
For Next.js, next dev --port 3002 --hostname 127.0.0.1 selects a local endpoint. When using an npm script, ensure arguments reach the underlying command.
Important limitations
3002 is an example, not a guaranteed free port. Do not expose a development server as a production service; update callbacks and proxy targets after changes.
Read-only checks: run on the server host
Choose the commands for your OS. Check TCP and UDP separately. No result is not a lasting availability guarantee; inspect host and container separately.
Linux
sudo ss -ltnp 'sport = :3000'macOS
sudo lsof -nP -iTCP:3000 -sTCP:LISTENWindows PowerShell
Get-NetTCPConnection -LocalPort 3000 -State ListenSources and review
Sources checked on:
This review covers the explanations and sources on this page, not your device or every community software entry below.
Software Using This Port (29 software)
Community software entries: links are references, not individual verification.
Node.js Development Server
Node.js is a runtime; the application chooses its listening port.
React Development Server
A React application uses the development port configured by its build tool or framework.
Usage Suggestions
- Before using port 3000, please confirm it is not occupied by other services
- If you encounter port conflicts, consider using other ports or stopping the occupying service
Quick Info
- Port
- 3000
- Protocol
- TCP
- Categories
- Development
- Usage Status
- 29 software in use
Related Ports
Need Help?
If you find incorrect information or need to add more, please submit correction information.
Submit Correction