:- use_module(library(http/thread_httpd)). :- use_module(library(http/http_dispatch)). :- use_module(library(http/html_write)). :- http_handler(root(hello_world), say_hi, []). server(Port) :- http_server(http_dispatch, [port(Port)]). say_hi(_Request) :- reply_html_page(title('Hello World'), [ h1('Hello World'), p(['This example demonstrates generating HTML ', 'messages from Prolog' ]) ]).