Type hn _ and the _ becomes the title of the current top Hacker News story. Press Ctrl+Alt+↑/↓ and you rotate through the rest of the frontpage without leaving your text field.
What you type
Two keywords: hn and hackernews, leading the sentence your _ ends. A keyword expansion renders the terse hn as HackerNews in the display layer. As with every keyword blank, the trigger has to lead its sentence, so writing about Hacker News mid-sentence never fires a fetch. The bare form wipes the command and leaves just the story title; copula phrasings (the top hn story is _) keep your lead-in text.
Where the data comes from
The official Hacker News Firebase API: one fetch for the top-story id list, then item fetches for the top 20 titles. No API key. The list is cached for 5 minutes, so repeated fills and cycling don't hammer the API.
This one cycles
Unlike the single-answer lookups (weather, stocks, dictionary), the Hacker News blank returns a list, one title per line, and the runtime registers the result as a cycleable span. The first title fills the blank; Up/Down rotates through the other nineteen. It's read-only in the external-state sense (cycling never changes anything in the world, unlike the volume blank), but it's the shipped example of a fetch blank whose alternatives are genuinely worth browsing.
With the optional blank-context-mode on, the current top story is also exposed as an ambient token, so casual phrasings like anything interesting on hn _ can route to it through the catalog without the exact keyword. The blank is also dismissible, so an unwanted fill is one keystroke from gone.
Related: What is a blank? · Keyboard navigation and cycling · GitHub repo