About this site

The Bot Ledger is a how-to for people building trading bots on prediction markets. The material comes from two months of live testing on Polymarket, Kalshi, Predict.fun and Limitless: hundreds of strategy variants, custom models, real money, and a long list of things that did not work.

What you will find here

The guides cover one exchange each: how to authenticate, read the order book, place and cancel orders, read your fills and handle settlement, with simplified Python and a prompt you can hand to an AI assistant. The articles cover the parts the API documentation leaves out: where to get historical data, what the fees really cost at each price, which server region keeps an edge alive, and what happens to an edge once other bots find it. The case studies walk through strategies that ran with real money, including the ones that lost.

How the numbers are handled

Case-study figures are scaled from logged runs so the stories read cleanly, and every page that uses them says so. Exchange facts, fees, settlement rules and dates are as observed, and each page carries the date it was true. APIs and rules change; check the exchange's own documentation before you trade.

What is not here

Nothing is for sale. No signals, no bot, no course, no gated content and no newsletter. Exchange or hosting affiliate links may appear on recommendations and are marked where they do. The site does not give financial advice and does not know your situation; the disclaimer explains what that means in practice.

Languages

Every page is available in English, Spanish, German, Portuguese and French. The English version is the source; the others are translations that follow it, and the selector in the header switches between them.