Execution-aware arbitrage and sentiment analytics for prediction markets. Arbiter is a trading intelligence layer built on top of Polymarket that helps users reason about real, executable opportunities instead of misleading headline odds. It combines order-book-aware simulations with sentiment context to show where apparent edges survive execution—and where they break.

Arbiter turns prediction markets into something closer to a real trading terminal. Core features Execution-aware arbitrage analysis Simulates real trades using Polymarket order books Computes size-adjusted execution prices Shows where arbitrage breaks due to slippage Profit vs size trade simulation Interactive slider to test different contract sizes Visualizes P&L curves instead of single-point estimates Slippage & volatility labeling Clear LOW / MEDIUM / HIGH slippage indicators Helps users quickly judge trade fragility Intra-market opportunity discovery Compares logically related Polymarket markets (subset, implication, etc.) Avoids fake arbitrage based on midpoint math Sentiment & narrative context (optional layer) Primarily uses Polymarket pricing as the belief signal Adds a lightweight narrative overlay from X (via Bird) as contextual support

Most prediction market tools treat price as probability and ignore execution. Arbiter explicitly models order-book depth, slippage, and size effects, revealing that many “arbitrage” opportunities disappear once real execution is considered. This is a feature, not a bug—and Arbiter makes that reality visible.

Frontend Next.js (App Router) React TypeScript Interactive charts for trade simulation and analytics Backend / API Next.js API routes / server actions TypeScript Execution simulation logic (order book walking, slippage modeling) Data & Infrastructure Polymarket APIs Gamma API (market discovery & metadata) CLOB API (order books, bids/asks, spreads) Supabase (Postgres) Market metadata Cached analytics Optional pgvector support for semantic search Vercel Hosting Serverless functions Scheduled cron jobs AI / ML OpenAI API Used as a conservative logical relationship classifier Identifies which market pairs have hard resolution constraints Prevents false arbitrage from weak semantic similarity Optional Narrative Layer Bird CLI (X/Twitter ingestion) Best-effort, cached narrative context Not a core dependency; Polymarket remains the primary signal

• frontend/: Next.js app (UI + API routes)

cd frontend
npm install
npm run dev

Then open http://localhost:3000.