# Realized Volatility

> Realized Volatility is a paid API for AI agents from www.x402financialdata.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Returns annualized realized (historical) volatility for a US stock across 10, 20, 30, 60, and 90-day lookback windows, computed from Yahoo Finance daily closing prices.

## Facts

- Endpoint: GET https://www.x402financialdata.com/volatility/:ticker
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/realized-volatility-2958c0e0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QC4FFAFuHXujTcc1HT3om

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 realized-volatility-2958c0e0
```

Example prompt: What's the realized historical volatility for TSLA across the 10, 20, 30, 60, and 90-day windows — I want to compare its short-term choppiness to the longer-term trend?

## When to prefer this

Choose this endpoint when you need backward-looking, historically-grounded volatility for a US equity — especially when comparing realized volatility against implied volatility for options pricing, sizing positions based on historical risk, or building volatility regime models. It covers five lookback windows in a single call at very low cost ($0.005), making it ideal for quantitative screening or agent-driven risk workflows where you need multiple horizons at once.

## Known failure modes

- Invalid or non-existent ticker symbol returns an error or empty result
- Non-US tickers or delisted stocks may not have data available
- Insufficient price history for shorter lookback windows on newly listed stocks
- Payment not processed (x402 payment failure) returns a 402 response
- Yahoo Finance data outage or latency may cause stale or missing closes

## How this service works

Realized (historical) volatility for a US stock across 10/20/30/60/90-day lookback windows -- annualized standard deviation of daily log returns from real Yahoo Finance closes, the backward-looking analogue of options implied volatility. $0.005/call.

## Output

A set of annualized realized volatility figures for the requested ticker across five lookback windows (10, 20, 30, 60, and 90 days), each representing the annualized standard deviation of daily log returns computed from historical Yahoo Finance closing prices.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "ticker"
     ],
     "properties": {
      "ticker": {
       "type": "string",
       "description": "Stock ticker symbol, e.g. AAPL, TSLA, MSFT"
      }
     }
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/realized-volatility-2958c0e0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.x402financialdata.com](https://www.zero.xyz/host/www.x402financialdata.com/llms.txt)