Localhost Port Lookup
Use the homepage lookup to identify common localhost ports and get a quick command for checking local port usage.
Fast checklist
- 1 Enter the port number you saw in a terminal, tutorial, or error message.
- 2 Check whether it is usually a browser page, API, database, or cache service.
- 3 Run the command for your operating system if you suspect a port conflict.
- 4 Open the browser URL only when the service is an HTTP server.
Quick diagnostic checks
lsof -i :3000Replace 3000 with the port you need. A listed process means something owns the port, but not always the app you expected.
localhost:3306MySQL, PostgreSQL, Redis, and MongoDB ports usually need a database client or connection string, not a web page.
http://localhost:8080/A port lookup tells you the common meaning. The browser response tells you what your current machine is actually serving.
Live request check
What this page sees
HTTP request headers
Sensitive headers such as cookies and authorization tokens are filtered before display.
Port lookup is not a guarantee
A port can be used by any application. The lookup shows common development patterns, not a verified scan of your computer.
Browser vs non-browser ports
Ports such as 3000, 5173, and 8080 often serve web pages. Ports such as 3306, 5432, and 6379 usually need specialized clients.
How to use the result
Treat the lookup as a clue, then confirm with your terminal, framework output, and the actual browser response.
- If the port is busy, identify the process before killing it.
- If the port is free, start the service or open the port printed by the service.
- If the service is not HTTP, use the matching CLI or desktop client.
Related localhost guides
localhost:3000
Open localhost:3000, learn which development servers commonly use port 3000, and fix connection errors quickly.
Port guidelocalhost:8080
Open localhost:8080 and learn why Java servers, Tomcat apps, local proxies, and admin tools often use port 8080.
TroubleshootingLocalhost refused to connect
Fix localhost refused to connect by checking the server process, URL, port, protocol, firewall, and local logs.
Developer toolLocalhost URL Builder
Build localhost URLs with the right protocol, host, port, and path, then compare localhost, 127.0.0.1, and LAN IP patterns.
FAQ
Can this page scan my local ports?
No. A static browser page should not silently scan your machine. Use your terminal or operating system tools when you need exact process information.
Why does a database port fail in the browser?
Database protocols are not HTTP pages. Use a database client such as a CLI, desktop client, or framework connection string.
Does this tool make network calls to third-party services?
The URL builder and port lookup run in the browser, and the request inspector uses this same site endpoint. Locallhost.im uses Pageview for basic pageview analytics, but the request inspector does not call a third-party IP lookup API.
Why should I copy the debug snapshot?
The snapshot gives a concise record of the URL, request line, safe headers, user agent, and browser context. It is useful when reporting a localhost issue to a teammate or coding assistant.
Are cookies and authorization headers shown?
No. Sensitive headers such as cookies, authorization, and common API token headers are filtered before display.