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x402-factory S&P 500 Positive This Year Probability
x402
x402-factory S&P 500 Positive This Year Probability is a paid API for AI agents from x402-factory.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).
Returns real-time prediction-market probability that the S&P 500 will finish the year positive (close above 7000 on Dec 31), aggregated across Kalshi and Polymarket, via micropayment (x402/USDC).
Price / call$0.02
Success—
StatusUnknown
How this service works
Paid data APIs for AI agents: prediction-market analytics, weather intelligence, weather×market edge signals, and SEC/gov data. Paid endpoints use the x402 protocol (HTTP 402 + USDC on Base): call without payment to receive requirements, retry with an X-PAYMENT header. Machine-readable catalog: /llms.txt. Per-endpoint docs: /docs/{id}.
Output
Returns a JSON object with the aggregated implied probability (e.g. 0.3812) that the S&P 500 closes above 7000 on December 31, per-venue breakdowns from Kalshi and Polymarket (each with implied probability, market ID, 24h USD volume, and liquidity score), a divergence score between venues, resolution date, resolution criteria summary, and metadata including data freshness and source list.
Example use cases
Equity outlook for portfolio review
“Before I rebalance my portfolio, what's the real-time prediction market consensus that the S&P 500 ends the year positive? Pull the Kalshi and Polymarket numbers and tell me if they disagree.”
Trading signal from cross-venue divergence
“Is there currently a notable spread between Kalshi and Polymarket on the S&P 500 finishing positive this year? I want to know the implied probabilities from each venue and the divergence score.”
Market sentiment check for macro report
“For my weekly macro briefing, give me the latest crowd-sourced probability that the S&P 500 closes above 7000 on December 31, including the 24-hour trading volume and liquidity scores from each prediction market venue.”
Technical details
Endpoint
GEThttps://x402-factory.com/v1/evergreen/sp500-positive-this-yearWhen to prefer
Choose this endpoint when you need a real-time, cross-venue aggregated probability for the S&P 500 annual outcome with liquidity and volume context. It is preferable to scraping Kalshi or Polymarket individually because it normalizes data across both venues, computes divergence, and provides a single consensus probability. Use it for macro research, portfolio decision support, or detecting arbitrage signals between prediction markets. Requires micropayment via x402 protocol (USDC on Base, $0.02/call).
Side effects
- HTTP 402 returned on first call without payment — agent must parse payment requirements and retry with X-PAYMENT header containing valid USDC on Base
- Insufficient USDC balance causes payment failure and request rejection
- Market may roll to next slug if resolution date passes — check current_slug in response
- Stale or unavailable venue data may reduce per_venue array to fewer than two entries
- Network timeouts if called during high-traffic periods on prediction market APIs
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| properties | string |
Output
Schema · Response
{
"type": "json",
"example": {
"data": {
"slug": "sp500-close-above-7000-2026-12",
"topic": "sp500-positive-this-year",
"category": "economics",
"question": "Will the S&P 500 close above 7000 on December 31?",
"per_venue": [
{
"venue": "kalshi",
"implied_p": 0.4022,
"market_id": "KXSP500CLOSEABOV",
"volume_24h_usd": 182273.22,
"liquidity_score": 0.921
},
{
"venue": "polymarket",
"implied_p": 0.367,
"market_id": "sp500-close-above-7000-2026-12",
"volume_24h_usd": 154584.53,
"liquidity_score": 0.949
}
],
"divergence": 0.0352,
"probability": 0.3812,
"current_slug": "sp500-close-above-7000-2026-12",
"last_move_1h": 0,
"topic_question": "Will the S&P 500 finish the year positive?",
"resolution_date": "2026-12-31",
"rolls_to_next_at": "2026-12-31",
"resolution_criteria_summary": "Resolves YES if the official closing level on the last trading day exceeds 7000."
},
"meta": {
"docs": "https://x402-factory.com/docs/probability.evergreen.sp500-positive-this-year",
"sources": [
"kalshi",
"polymarket"
],
"version": "1.0.0",
"endpoint": "/v1/evergreen/sp500-positive-this-year",
"data_mode": "live",
"freshness": "realtime",
"request_id": "req_00000000",
"generated_at": "2026-08-21T03:58:58.097Z"
}
}
}Tags
x402
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