# Vextorium Polymarket History

> Vextorium Polymarket History is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-19).

Fetches historical probability time-series data for a Polymarket prediction market by slug, including current probability, min/max, and change over a chosen interval.

## Facts

- Endpoint: POST https://api.vextorium.com/v1/polymarket-history?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/vextorium-polymarket-history-4c5d825f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Gv4za065pqkblqFyq700q

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability vextorium-polymarket-history-4c5d825f -d '<json body>'
```

Example prompt: Pull the daily probability history for the Polymarket market 'will-oprah-winfrey-win-the-2028-democratic-presidential-nomination', outcome index 0, using the 1d interval — show me the current probability, the min/max, and how much it's changed.

## When to prefer this

Use this endpoint when you need historical probability data for a specific Polymarket prediction market, particularly for time-series charting, trend analysis, or monitoring how crowd-sourced event probabilities have evolved. Prefer this over generic DeFi data endpoints when the user explicitly references Polymarket markets or prediction market odds.

## Known failure modes

- Invalid or non-existent slug returns an error or empty result
- Outcome index out of range returns null or error
- Unsupported interval value rejected at schema validation
- Market with insufficient history may return a sparse or empty series
- Network timeout or upstream Polymarket API unavailability

## How this service works

558 pay-per-call data APIs for AI agents: Solana and EVM on-chain data, tokenized stocks, DeFi, Hyperliquid, economy and official statistics, FX, validation, web and developer tools. Pay in USDC via x402.

## Output

Returns a JSON object with the market question text, the outcome label (e.g. 'Yes'), a time-series array of {date, probability_pct} objects, the current probability percentage, min/max probabilities over the period, the interval used, and the change in percentage points.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "slug": {
   "type": "string"
  },
  "result": {
   "type": "integer",
   "description": "Outcome index (0 = first)"
  },
  "interval": {
   "enum": [
    "1h",
    "6h",
    "1d",
    "1w",
    "1m",
    "max"
   ],
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": "Yes",
  "series": [
   {
    "date": "2026-10-01T20:30+00:00",
    "probability_pct": 0.05
   },
   {
    "date": "2026-10-01T21:00+00:00",
    "probability_pct": 0.05
   }
  ],
  "max_pct": 0.05,
  "min_pct": 0.05,
  "interval": "1d",
  "question": "Will Oprah Winfrey win the 2028 Democratic presidential nomination?",
  "change_pp": 0,
  "current_probability_pct": 0.05
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/vextorium-polymarket-history-4c5d825f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.vextorium.com](https://www.zero.xyz/host/api.vextorium.com/llms.txt)