Take the url of any submission (comment/story...) and you might have noticed the item?id attribute.<p>For example:
https://news.ycombinator.com/item?id=30070369<p>For a personal project, I am wondering if this number is always increasing, upon each new story or comment, or does it happen that lower identifiers are re-used when a new submission is published?<p>Is there any reference or documentation on this particular field?