Best Open Source Prediction Markets (2026)

Polyrama is a real-time prediction-market terminal for Polymarket and Kalshi. It combines live odds, cross-venue market search, public-wallet analytics, trader leaderboards, whale and mispricing signals, dashboard state, historical backtests, REST API access, and an open-source MCP server for AI agents. The MCP exposes research and paper-trading tools only; it does not place live orders.

The Overround

The Overround compares the same event across Kalshi, Polymarket and a panel of nine US sportsbooks, normalises the prices so they can be read against each other, and shows which venue is cheapest to back a given side. It also publishes the overround on each market, the sum of what it costs to back every outcome at each venue, so you can see what the house is charging before you trade. Every market gets its own page carrying the full field, the settlement source and the contract terms. Free, no account, and the underlying data is available as unauthenticated JSON.

Coinverse

Are you ready to take your trading to the next level? Experience the power of a prediction market with Coinverse! Join us now! #Coinverse #TradingRevolution #JoinNow

socialpredict

The open prediction market engine for everyone SocialPredict lets anyone – individuals, classrooms, companies, and even governments – tap into the power of prediction markets.

Polygun

Sophisticated automated trading bot for position mirroring.

Building tools & community resources to bring Polymarket into everyday lexicon

No-code playground for building & sharing AI agents

Prediction market protocol on Polkadot with categorical and scalar markets.

Pioneer decentralized prediction market protocol and oracle on Ethereum.

Futarchy-based governance protocol on Solana using prediction markets for decision-making.