✓ Checked 2026-10-17
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Prediction market APIs and AI agents (2026)
⚠ Risk note. Prediction markets can go to zero on a single outcome, liquidity can vanish near resolution, and rules on who may trade differ sharply by country. Polymarket's international site is close-only for US persons (US residents use the separate Polymarket US); Kalshi is a US exchange with limited non-US access. Using a VPN to get around a geoblock breaks the venues' terms and can get funds frozen. Not financial advice.
| Tool | Live / paper | Safety and access | Pricing | Regions | Visit |
|---|---|---|---|---|---|
| Kalshi API | live; separate demo environment with mock funds (demo.kalshi.co) | official REST and WebSocket Trade API with RSA-PSS or Ed25519 signed keys; demo credentials are separate from production; no official MCP (community MCPs exist) | API access free; exchange trading fees apply per contract | US: yes (CFTC-regulated exchange); some contracts may be restricted in some states. Non-US access is limited: check Kalshi's eligibility page for your country. | Visit Kalshi API |
| Polymarket API | live only (no testnet); CLOB V2 since Apr 28 2026 | wallet-signed orders on the international CLOB (V2 SDKs: py-clob-client-v2, clob-client-v2); separate Polymarket US API with Ed25519 keys and an order preview endpoint | API access free; trading fees vary by market | International polymarket.com: US persons cannot open positions (US is close-only) and other jurisdictions are blocked. US residents: use Polymarket US (separate CFTC-regulated app, ID-verified, separate API). | Visit Polymarket API |
| Polymarket Agents | live (trades via the Polymarket API) | official open-source framework (MIT) with LangChain/Chroma RAG, news sourcing and a CLI that can execute trades; check it targets CLOB V2 before trading | free, open source | Polymarket's terms bar US persons and other restricted jurisdictions from trading through the international API, including via agents. | Visit Polymarket Agents |
| Polymarket US API | live | official Python and TypeScript SDKs; orders support preview, cancel and cancel-all; keys need an ID-verified Polymarket US account | API access free; trading fees per Polymarket US schedule | US residents only, via the Polymarket US iOS app with identity verification. | Visit Polymarket US API |
| Limitless Exchange | live only; no sandbox or testnet (docs say rehearse with minimum-size live orders) | official trading MCP at api.limitless.exchange/mcp with a human approving each order in chat; open-source agents-starter repo runs dry-run by default | API access free; trading fees per market | Check Limitless's terms for restricted jurisdictions before trading. | Visit Limitless Exchange |
| Manifold Markets API | play money (mana); no real-money risk | bots and automated trading explicitly permitted; API keys per user; good for testing agent logic without real money | free | Available globally (play money). | Visit Manifold Markets API |
| Kalshi MCP Server (community) | demo and live; trading off by default | community MIT MCP: two-step prepare/confirm order flow, safety caps that can only be tightened at runtime, demo mode, client-side rate limiting | free, open source | Same eligibility as Kalshi. | Visit Kalshi MCP Server (community) |
| Prediction.Markets API | data only (no execution) | read-only unified API and MCP across venues with a consensus probability; MIT-licensed MCP | free during beta (1,000 req/day); paid tiers announced | Data viewable globally. | Visit Prediction.Markets API |
Where to start
- US residents: Kalshi (demo first) or Polymarket US.
- Outside the US: the international Polymarket CLOB (V2 SDKs only since Apr 28 2026) or Limitless on Base, if your country is allowed.
- Testing agent logic: Manifold's play-money API or Kalshi's demo.
Agent safety basics are on Risk and safety tools and Broker MCP safety controls.
✓ Checked 2026-10-17
✓ Checked 2026-10-17
✓ Checked 2026-10-17
✓ Checked 2026-10-17
✓ Checked 2026-10-17
✓ Checked 2026-10-17
✓ Checked 2026-10-17
FAQ
Can US residents trade Polymarket with an API or agent?
Not on the international polymarket.com: the US is close-only there, and Polymarket's own Agents repo says US persons may not trade through the API or agents. US residents can use Polymarket US, a separate CFTC-regulated app with its own ID-verified accounts and API.
Is Kalshi available outside the US?
Kalshi is a CFTC-regulated US exchange. Non-US access is limited and changes; check Kalshi's eligibility page before building on it.
Which prediction markets have a sandbox?
Kalshi has a full demo environment with mock funds. Manifold uses play money, so it is a safe place to test agent logic. Polymarket and Limitless have no testnet; their docs suggest minimum-size live orders.
Is there an official prediction market MCP?
Limitless runs an official trading MCP at api.limitless.exchange/mcp. Kalshi and Polymarket have community MCP servers only, as of October 2026.