Last updated: August 2026
Arbitrage Betting API
REST API for prediction market arbitrage — Polymarket, Kalshi, and Opinion pairs with fee-adjusted ROI, orderbooks, and stake sizing for bots and agents.
What is an arbitrage betting API?
An arbitrage betting API lets developers query live cross-platform mispricings instead of building matching logic from scratch. ArbBets returns normalized pairs, full orderbooks, and pre-computed spreads so your agent can alert or trade when combined ask prices fall below $1.00 after Kalshi fees.
- 990+ matched markets — politics, macro, crypto, sports events
- Fee-adjusted ROI — Kalshi 7% taker model baked in
- Investment sizing — pass a dollar budget; get per-leg contract counts
Arbitrage bets API — quick start
The primary arbs API endpoint scans Kalshi and Polymarket orderbooks and returns actionable opportunities:
curl -H "Authorization: Bearer YOUR_API_KEY" \ "https://getarbitragebets.com/api/internal/arbs-full_2?investment=100&min_profit=1.9"
Full parameters, response format, and Python examples are in the arbitrage betting API docs.
Arbs API vs scanner dashboard
| Use case | Best option |
|---|---|
| Manual trading, alerts | Arbitrage bet finder (Pro scanner) |
| Bots, agents, custom dashboards | Arbitrage betting API (Premium) |
| Stake sizing without API | Kalshi arbitrage calculator |