Port Number Reference

A port number is a 16-bit value (0–65535) that identifies a specific service or process on a device. Combined with an IP address, it forms a socket: the IP finds the host, the port finds the service on that host. For example, web servers listen on 80 (HTTP) and 443 (HTTPS), email uses 25/587 (SMTP) and 993 (IMAPS), and databases use 3306 (MySQL) or 5432 (PostgreSQL).

Well-known ports run from 0 to 1023 and are reserved by IANA for core system services — for example 22 SSH, 53 DNS, 80 HTTP, and 443 HTTPS. On Unix-like systems only privileged processes may bind them. These are followed by registered ports (1024–49151) for common user applications and dynamic/private ports (49152–65535) used for ephemeral client connections.

TCP is connection-oriented and guarantees ordered, error-checked delivery — used by HTTP, SSH, SMTP, and MySQL. UDP is connectionless and faster, with no delivery guarantees — used by DNS queries, NTP, streaming, VoIP, and gaming. Many services use the same port number for both, but they are separate name spaces and can host different services.

The same port number is often assigned to multiple services — a port number alone cannot identify a service; the protocol (TCP or UDP) and the application convention matter too. For instance 8080 is used by dozens of dev servers and proxies, and 5000 is shared by AirPlay and Flask. The context of the conversation usually resolves the ambiguity.

3000 (Node/React/Astro dev servers), 8080 and 8000 (common web/dev ports), 8888 (Jupyter), 4000 (Phoenix), 5000 (Flask), 5432 (PostgreSQL), 3306 (MySQL), 6379 (Redis), 27017 (MongoDB), 9200 (Elasticsearch), 9092 (Kafka), and 25565 (Minecraft). The database of this tool covers all of these and more.

An ephemeral (dynamic) port in the range 49152–65535 is chosen at random by the operating system for the client side of a connection. It exists only for the duration of that connection and frees the well-known and registered ranges for server services. This is why clients can make many simultaneous connections to the same server port.

Port 80 is the standard, IANA-assigned port for HTTP. Port 8080 is an unofficial alternate commonly used for development, proxies, and administration tools so that they can run alongside a production web server already using 80 or 443. Browsers treat 80 and 443 as the defaults and hide them from the address bar, while other ports must be written explicitly (e.g. http://localhost:8080).

Yes — completely free, no registration, and 100% private. The full port database ships with the page and runs locally in your browser; searches and lookups are never sent to any server. It works offline once loaded.