I built an interactive HN Simulator

Details

External ID

46036908

Source

HN

Company

—

Product

I built an interactive HN Simulator

Website domain

ysimulator.run

Launched

Nov. 24, 2025

Cohort

—

Upvotes

538

Upvotes percentile

0.9890829694323144

Tags

—

Fetched at

Sept. 7, 2026, 9:25 p.m.

Updated at

Sept. 7, 2026, 9:25 p.m.

Description

Hey HN! Just for fun, I built an interactive Hacker News Simulator.You can submit text posts and links, just like the real HN. But on HN Simulator, all of the comments are generated by LLMs + generate instantly.The best way to use it (IMHO) is to submit a text post or a curl-able URL here: https://news.ysimulator.run/submit. You don't need an account to post.When you do that, various prompts will be built from a library of commenter archetypes, moods, and shapes. The AI commenters will actually respond to your text post and/or submitted link.I really wanted it to feel real, and I think the project mostly delivers on that. When I was developing it, I kept getting confused between which tab was the "real" HN and which was the simulator, and accidentally submitted some junk to HN. (Sorry dang and team – I did clean up after myself).The app itself is built with Node + Express + Postgres, and all of the inference runs on Replicate.Speaking of Replicate, they generously loaded me up with some free credits for the inference – so shoutout to the team there.The most technically interesting part of the app is how the comments work. You can read more about it here, as well as explore all of the available archetypes, moods, and shapes that get combined into prompts: https://news.ysimulator.run/comments.htmlI hope you all have as much fun playing with it as I did making it!

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