Polymarket arbitrage bots

Prediction markets turn a question into two tradeable tokens, and on Polymarket the winning token redeems for $1 while the loser goes to $0. A bot can try to lock in a spread by buying both sides cheaply enough before the market resolves. (docs.polymarket.com) That is the setup behind a batch of open-source Polymarket trading bots published by GitHub user crellios, including a repository with 101 stars and 41 forks for 15-minute crypto “Up/Down” markets. The code is written in Rust and targets Bitcoin, Ethereum, Solana, and XRP contracts. (github.com) The main repo says the bot places limit buy orders on both the Up and Down tokens before or at the start of each 15-minute period. If both orders fill below the bot’s price cap, the position is designed to settle for a small fixed profit when one side pays $1. (github.com) Polymarket’s market structure makes that automation possible because trading runs through a central limit order book, or a live list of bids and offers, with offchain matching and onchain settlement on Polygon. The company also publishes official software clients and authentication methods for programmatic trading. (docs.polymarket.com, github.com) The crellios repo describes this as “pre-order arbitrage,” but the mechanics are closer to automated market making around short-dated binary contracts. The bot watches the current and next 15-minute windows, discovers markets through Polymarket’s Gamma API, and can skip or exit trades using signal-based risk rules. (github.com) A separate crellios repo describes a different strategy for BTC and ETH 15-minute and 1-hour binaries. That version says it uses outcome prices from Gamma and short-term token price trends to place batches of limit orders on the side it thinks is both more likely to win and already moving higher. (github.com) The edge these bots chase is small and mechanical: if Up and Down can be bought for less than $1 combined, the spread is the profit before fees, slippage, and execution risk. If only one side fills, or a market resolves late or gets disputed, the trade stops looking like a clean arbitrage and starts looking like directional exposure. (docs.polymarket.com, github.com) Polymarket’s own resolution docs spell out that markets can face a proposal, a two-hour challenge period, and in some cases disputes that escalate to a UMA vote. That means “risk-free” language used around prediction-market bots often depends on both legs filling and the market resolving as expected. (docs.polymarket.com) The repositories also show how much of Polymarket trading has moved from one-off bets to infrastructure work: API keys, wallet signatures, proxy addresses, order routing, and redemption logic. In that sense, the code is less a novelty than a public blueprint for how traders automate a market built to look like a sportsbook and behave like an exchange. (docs.polymarket.com, github.com, github.com)