I was poking around at the "fetch title" function on new submissions because I wanted to use it in a personal project and I found that fetching the title of a HN submission won't work.

If you put a url from a HN thread like "https://news.ycombinator.com/item?id=13069841" and click fetch title you will get "null value not allowed" as the title.

HN uses this to fetch titles: https://textance.herokuapp.com/