Show HN: Infinite Swap – Trade a bottle cap up to a house

Infinite Swap is a game inspired by Kyle MacDonald’s One Red Paperclip and other bigger-and-better swap stories - you start with a green bottle cap and trade it with other characters in various locations all the way up to a house and beyond.

A while ago I got inspired by viral games Infinite Craft and What Beats Rock? and wanted to make my own ‘exploring a LLM’s latent space’ style challenge. After much experimentation this became a trading style game, where the LLM comes up with all the items, trading scenarios and value estimates, which ended up being surprisingly fun and somewhat of a roller coaster to play.

I found it was the most intriguing if I separated the item offer from its valuation - so I implemented a pricing oracle called “Sal” who gives this info with his, sometimes snarky, opinion after each trade.

The item offer mechanism goes deeper too - each character’s profile is combined with a set of hidden motivations. I then use embeddings and cosine similarity to represent the desire the character has for the player's item, and therefore what they are willing to offer in exchange.

Links to play: iOS (small number of ads, polished): https://apps.apple.com/us/app/infinite-swap/id6761694545 Android (small number of ads, polished): https://play.google.com/store/apps/details?id=com.squizsoftw... Web (no ads, a touch rougher than the mobile versions but still very functional): https://infiniteswap.app

Stack: GPT-4.1-mini for item generation, SDXL Lightning for item images, Kokoro for voices (the latter two running on my 4090 at home). Postgres + FastAPI on k3s for the backend, native Swift/Kotlin for mobile, React for web.

Keen for any feedback, bug reports, improvement suggestions, etc. I’ll be around for a few hours if you have any questions.

Daniel