volumemaster2

Inspiration

For this project, I was inspired by Jane Street's manipulation of Indian options markets. I imagined that this form of market manipulation could easily occur in similar markets across online prediction markets where the market being traded on is substantially smaller than the total trading volume. One market fits this characteristic well: Kalshi's prediction market on the prices of Pokemon products.

What it does

This extension uses a data pipeline from Kalshi (for price and market data) --> TCGCSV (to match product prices to listings) --> Apify (to scrape sales volume over weeks/months). This pipeline runs once a day in order to minimize Apify usage and make it possible to run this project on the free plan. The extension then displays these findings on the Kalshi dashboard when you visit the site, along with warnings next to markets that have dangerous levels of trading volume compared to low activity in the underlying market.

How I built it

I worked with Claude Code to integrate these various tools. I created the data ingestion points in Python and then used generative AI to connect them and incorporate measures to reduce API calls (such as by only gathering data on products listed as currently active on Kalshi). I then communicated with Claude Code to create the extension and UI/UX elements.

Challenges I ran into

This project was very cut-and-dry, and due to being a one-person project I had full creative control. Therefore, most of the challenges I ran into had to do with technical execution. A particularly confounding challenge is TCGPlayer's lack of API access, which goes back years. They do not allow web scraping of their site, so I needed to work several 3rd party APIs in order to get the information I needed.

Accomplishments that I'm proud of

I'm proud of designing a product that can help keep people informed when gambling. If you're going to risk your money on a prediction market like Kalshi, you'd do better to at least avoid markets that can be easily manipulated. It was also a fun exercise in working with the Kalshi and TCGCSV APIs, which I may use in future projects.

What I learned

I learned a good bit about how prediction markets work and the legal frameworks that make them possible. I have a more negative overall sentiment toward online prediction markets.

What's next for volumemaster2

In an ideal world, I would get approved for access to the TCGPlayer API and Collectr API, which would allow us to shed the dependency on Apify. I would also like the opportunity to extend this extension to different prediction markets and types of prediction.

Built With

• apify
• kalshi-api
• tcgcsv