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  3. /Show HN: I built an interactive HN Simulator
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  3. /Show HN: I built an interactive HN Simulator
Nov 24, 2025 at 12:52 PM EST

Show HN: I built an interactive HN Simulator

johnsillings
1 points
0 comments

Mood

excited

Sentiment

positive

Category

startup_launch

Key topics

Hacker News

Simulator

Llms

Node

Express

Postgres

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.html

I hope you all have as much fun playing with it as I did making it!

Discussion Activity

Active discussion

First comment

2h

Peak period

20

Hour 7

Avg / period

13.6

Comment distribution122 data points
Loading chart...

Based on 122 loaded comments

Key moments

  1. 01Story posted

    Nov 24, 2025 at 12:52 PM EST

    11h ago

    Step 01
  2. 02First comment

    Nov 24, 2025 at 3:04 PM EST

    2h after posting

    Step 02
  3. 03Peak activity

    20 comments in Hour 7

    Hottest window of the conversation

    Step 03
  4. 04Latest activity

    Nov 24, 2025 at 11:50 PM EST

    12m ago

    Step 04

Generating AI Summary...

Analyzing up to 500 comments to identify key contributors and discussion patterns

Discussion (0 comments)

Discussion hasn't started yet.

ID: 46036908Type: storyLast synced: 11/24/2025, 5:54:10 PM

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