How I Reverse-Engineered Hacker News

Hacker News has a public API, and it’s great. Live front page updates, live upvote counts, live comments. Everything you want or need at the tip of your fingers in real-time.
But there’s no write. You can’t log in, you can’t upvote, and you can’t post. You can’t do anything but read. And you need writes to make a Hacker News App.