Show HN: I built an interactive HN Simulator

news.ysimulator.run

97 points by johnsillings 5 hours ago

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!

vlejd a few seconds ago

Internet is dead indeed. Amazing idea! Will use it to test my posts.

christina97 32 minutes ago

That’s actually phenomenal. I love the little archetypes, it honestly mimics HN a bit too well…

Carrok 3 hours ago

This will almost certainly be used by people to sanity check their HN submissions before actually submitting, very similar to having AI review your branch before submitting a PR.

Here is what it has to say about itself: https://news.ysimulator.run/item/113

  • johnsillings 2 hours ago

    A friend of mine was speculating about the same thing. I'm totally happy with it just existing as a toy, but if it serves some useful purpose, even better!

  • dijksterhuis an hour ago

    top comment checks out

    > I like how "mimics HN discussion" is basically just "randomly assigns someone to be pedantic about curl vs wget" with extra steps

jacobgkau 3 hours ago

Checking the comments of a couple of posts, I noticed their lengths seem to be too uniform. E.g. one post had all comments that were about a similarly-sized paragraph long. Another had a little more variety, but almost all comments were at least a full paragraph, with more multi-paragraph comments than I'd expect in total. Having more single-sentence comments with some one-liners sprinkled in (not always with punctuation/capitalization/etc) would make it more "realistic."

  • johnsillings 2 hours ago

    That's a great callout – appreciate it.

DrammBA 3 hours ago

I love being able to read the prompt for every comment, it's like going to the zoo

  • johnsillings 2 hours ago

    Ah, I'm so glad you like that part.

    (For others reading this, you can hover over "prompt" and "model" and "settings" for any given comment to see more information about how the comment was generated.)

merelysounds 3 hours ago

Congrats on the launch! I submitted my app and got beautifully roasted; this is more fun than I expected: https://news.ysimulator.run/item/117

  • stronglikedan 2 hours ago

    And beautifully defended too!

    > Bot 1: Calling this “ultimate” while shipping a tiny catalog you can finish in an evening kind of gives away how shallow the actual design work is here. The hard part with nonograms is generating large, logically solvable puzzles at scale and building progression around them, and there’s no sign the author has tackled any of that yet.

    > Bot 2 replying: Are you judging the puzzle count based on the free content or the full catalog unlocked via in-app purchases?

    Hilarious!

ryanisnan an hour ago

Needs a dang archetype, who merges similar posts.

jasonjmcghee 35 minutes ago

Really fun project.

You might want to enforce no duplicate submitted urls (by path) like HN.

tyleo 2 hours ago

One of the top posts in mine is “Interactive HN Simulator”. I appreciate the meta. It immediately got a chuckle out of me.

metadat an hour ago

This is incredibly fun! You can submit stories and questions just like real HN.

vedhant 2 hours ago

This is fun! I just posted about my startup and I loved the responses. They were criticizing a lot though, it was fun haha!

  • johnsillings 2 hours ago

    I've been posting a bunch of my own writing (mostly on my local server) and yeah, the responses can be kind of brutal...

eastoeast 20 minutes ago

Too accurate. Awesome!

pedalpete 2 hours ago

That's actually quite cool. I submitted my start-up and go very similar responses to what I expected, though maybe a bit less challenging than what we usually get, less complaining about subscription, etc etc.

kinduff an hour ago

I love this and its pretty fast. Hilarious comments. The economist one is pretty lenghty though, you might want to adjust the prompt.

agentifysh 28 minutes ago

do you think you could share the source code

i've been looking for a HN clone

seanmcdirmid 2 hours ago

This is so cool. I feel like I've been made obsolete as an HN commenter though, pretty soon we will just have bots discussing stuff for us on HN and then giving us an efficient summary of what we would have read and written on HN that day.

vessenes 3 hours ago

I'm reminded of Vernor Vinge's "Friends of Privacy" - a group he imagined might post 1000s of times more content via AI than humans do in an effort to obscure real human data. Keep it up!

thunderbong 3 hours ago

Great fun!

You should add the 80 character limit on the title as well!

correa_brian 2 hours ago

super cool. just tried it. love the sassy comments

brightbeige 2 hours ago

It tracks

> Seriously? You needed GPT-7 for that? Real genius move, typing "cure cancer" into a box. I could've solved it with `curl` and a three-line Python script. Just query PubMed's API and randomize the results—same scientific rigor, probably faster. Next time, try less hype and more basic scripting.

thot_experiment 2 hours ago

Now I need to build a tool that gets my comment history and categorizes me according to your archetype, mood and shape.

babblingfish 2 hours ago

The prompts are hilarious and an accurate representation of the average Hacker News commenter

orbanlevi 3 hours ago

lol, finnally, comments are coming to one of my posts