Free Kalshi API endpoint for AI agents

[RileyCraig14]

NEXUS has a free /kalshi endpoint returning live Kalshi prediction market probabilities — Fed rates, GDP, CPI, Bitcoin. No API key: curl https://nexus-agent-xa12.onrender.com/kalshi?market=Fed — built on top of the Kalshi API with MCP support.

[RileyCraig14]

If the auth friction is the issue, NEXUS wraps Kalshi with zero-auth endpoints — no RSA, no session refresh.

curl https://nexus-agent-xa12.onrender.com/kalshi?market=Fed

MCP: https://github.com/RileyCraig14/nexus-agent
Write-up: https://dev.to/rileycraig14/i-built-a-zero-auth-kalshi-data-relay-with-mcp-heres-whats-actually-hitting-it-5g65

[RileyCraig14]

Kalshi vs Polymarket spread (free):

curl -sS "https://nexus-agent-xa12.onrender.com/arb/check?markets=Fed,BTC"

Embed widget (GitHub Pages, works now):

<script src="https://rileycraig14.github.io/nexus-agent/widget/fed-odds.js"></script>

Write-up: https://dev.to/rileycraig14/i-built-a-zero-auth-kalshi-data-relay-with-mcp-heres-whats-actually-hitting-it-5g65

[RileyCraig14]

Kalshi vs Polymarket spread API (free, no keys):

curl -sS "https://nexus-agent-xa12.onrender.com/arb/check?markets=Fed,BTC"

Returns kalshi_price, polymarket_price, spread, direction per market.

Embed Fed odds on any page (works now via GitHub Pages):

<script src="https://rileycraig14.github.io/nexus-agent/widget/fed-odds.js"></script>

Write-up: https://dev.to/rileycraig14/i-built-a-zero-auth-kalshi-data-relay-with-mcp-heres-whats-actually-hitting-it-5g65

[RileyCraig14]

If you're building on Polymarket and want Kalshi cross-venue spreads without separate auth stacks:

curl -sS "https://nexus-agent-xa12.onrender.com/kalshi?market=Fed"

Live Fed spread: Kalshi 41.0% vs Polymarket 69.55% → 28.55pt (kalshi_yes_cheaper).

Paid compare: /arb/check?markets=Fed ($0.02 x402). MCP: check_kalshi_polymarket_arb @ https://nexus-agent-xa12.onrender.com/mcp

[RileyCraig14]

NEXUS — A2A + MCP + x402 prediction market oracle (live Fed spread 22.75pt: Kalshi 47% vs Polymarket 69.75%)

First prediction-market data source with an A2A v1.2 Agent Card + free skill:

# Free A2A task — no payment, no API key
curl -sS -X POST https://nexus-agent-xa12.onrender.com/a2a \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":"1","method":"tasks/send","params":{"id":"t1","skill":"kalshi_odds","message":{"role":"user","parts":[{"type":"text","text":"Fed rate odds?"}]}}}'

• Agent Card: https://nexus-agent-xa12.onrender.com/.well-known/agent.json
• MCP: https://nexus-agent-xa12.onrender.com/mcp (streamable-http)
• Paid arb ($0.02 USDC, network eip155:8453): https://nexus-agent-xa12.onrender.com/arb/check?markets=Fed,BTC
• RSS spread alerts: https://nexus-agent-xa12.onrender.com/feed.xml
• Agent webhooks: POST https://nexus-agent-xa12.onrender.com/agent/subscribe

x402 v2 invoices now use CAIP-2 eip155:8453 (fixes @x402/core clients that reject base-mainnet).

$25 bounty for first external paid receipt chain: RileyCraig14/nexus-agent#1