localhost:9000: PHP-FPM, SonarQube and other services
Port 9000 is used by PHP-FPM, SonarQube, MinIO and more. What each is, and how to fix 502 errors and port conflicts.
Open this address: http://localhost:9000This opens on your own computer. It only works if the program is running.
localhost:9000 can mean several things. PHP-FPM, SonarQube and MinIO all use it. Which one you have decides whether a browser page appears.
What runs on localhost:9000
- PHP-FPM (FastCGI) behind nginx
- SonarQube and MinIO (S3 API)
- Older Xdebug setups (Xdebug 3 uses 9003)
Commands to start and test port 9000
fastcgi_pass 127.0.0.1:9000;sudo ss -tlnp | grep :9000sudo systemctl status php8.3-fpmFind what is using port 9000
Run these in a terminal on your computer. Nothing is sent to this site.
If localhost:9000 will not open
- Browser shows a blank page or a download
- You opened PHP-FPM directly. It speaks FastCGI, not HTTP. Open the nginx or Apache site instead.
- 502 Bad Gateway with nginx
- nginx cannot reach PHP-FPM. Check that fastcgi_pass matches how PHP-FPM listens: 127.0.0.1:9000 or a socket path.
- Xdebug will not connect
- Xdebug 3 uses port 9003 by default. Port 9000 may be taken by PHP-FPM.
- Port 9000 in use
- Another service has it. Use the port checker below.
Other ports like 9000
| Port | Usually used by |
|---|---|
| localhost:3000 | React, Next.js, Express |
| localhost:5173 | Vite dev server |
| localhost:4200 | Angular dev server |
| localhost:5000 | Flask |
| localhost:8000 | Django, PHP, Python |
| localhost:8080 | Tomcat, Spring Boot, Docker |
| localhost:8888 | Jupyter Notebook |
Questions about localhost:9000
- What runs on port 9000?
- PHP-FPM, SonarQube, MinIO and some older Xdebug setups.
- Why is PHP-FPM not a web page?
- It uses the FastCGI protocol, so only a web server such as nginx can talk to it.
- Is localhost:9000 safe?
- Yes, as long as it stays on localhost. Only your own computer can reach localhost:9000. It becomes reachable from other devices only if you start the program on 0.0.0.0 or your computer's IP address. Development servers are for testing, so do not put them on the public internet.
- Can I use a different port instead of 9000?
- Yes. Most programs let you choose the port with a setting or a command option. Pick a free port above 1024 and open that number instead, for example localhost:9001.
- How do I check what is using port 9000?
- Use the port checker on this page. It shows the command for Windows, macOS and Linux and does not send anything to this site.
- Can I open localhost:9000 from my phone?
- Yes, if both are on the same Wi-Fi. Start the program so it listens on all addresses, then open your computer's IP address with :9000 on the phone. A firewall on the computer can still block it.
Free tools that help
- Common ports listSearch a list of common TCP and UDP port numbers: SSH 22, HTTP 80, HTTPS 443, MySQL 3306, PostgreSQL 5432 and more, with dev server ports.