A port is a software construct often used for multiplexing an IP address. Like a single apartment building having multiple apartments, a single IP address can have multiple ports.
Port numbers are appended to the end of an IP address with a colon to form a socket. In the following example, a Postgres database, a Node.js API and a React frontend application each share localhost but open different sockets—listening on ports 5432, 8080 and 3000, respectively:
http://127.0.0.1:5432 (database)
http://127.0.0.1:8080 (API)
http://127.0.0.1:3000 (frontend)
The HTTP Port specified in your Uffizzi app configuration is the port at which your app is listening for incoming HTTP requests - providing the port number that listens to the ingress service is required with Uffizzi. Note you can only assign one container in a multi-container deployment as the container that listens for incoming requests.