# DripMetrics Roll Spread

> DripMetrics Roll Spread is a paid API for AI agents from api.dripmetrics.ai, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-11, last successful call 2026-06-15).

Calculates the Roll spread proxy metric — an estimate of bid-ask spread derived from lagged price covariance — for a crypto trading pair on Binance or Coinbase over a 30m or 1h window.

## Facts

- Endpoint: GET https://api.dripmetrics.ai/metrics/roll-spread?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Last successful call: 2026-06-15
- Success rate: 71% of calls made through Zero
- Rating: 4.0 / 5 from 1 review
- Activations on Zero: 8
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-dripmetrics-ai-a60c567b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XfJ7eG0YUSPZ_edVHQTyL

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 api-dripmetrics-ai-a60c567b
```

Example prompt: What's the Roll spread for BTCUSDT on Binance over the last 1 hour? I want to estimate the implied bid-ask spread using lagged price covariance.

## When to prefer this

Use this endpoint when you need a fast, on-demand, pay-per-call Roll spread estimate for Bitcoin or Ethereum pairs on Binance or Coinbase without managing subscriptions or API keys. Prefer it over subscription-based data feeds when cost efficiency and agent-native x402 micropayments matter, or when you specifically need the Roll (1984) covariance-based spread proxy rather than order book derived spreads.

## Known failure modes

- Unsupported exchange or pair symbol returns a 4xx error
- Insufficient trade data in the window may yield low tradeCount or no result
- Payment failure via x402 returns 402 Payment Required
- Invalid window value (not '30m' or '1h') returns validation error
- Network or upstream exchange data outage returns 5xx

## How this service works

DripMetricsAI (https://dripmetrics.ai/) provides on-demand crypto market microstructure metrics, Hyperliquid candle metrics, Polymarket diagnostics, and on-chain DefiLlama metrics for agents, dashboards, and trading workflows.

## Output

Returns a structured JSON object with the Roll spread value (a numeric spread proxy in price units), the covariance and number of intervals used in the computation, trade count, the pair/exchange/window parameters, and the timestamps of the first and last trade included plus when the metric was computed.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "pair": "BTCUSDT",
   "window": "1h",
   "exchange": "binance"
  }
 }
}
```

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "pair",
      "exchange",
      "window"
     ],
     "properties": {
      "pair": {
       "type": "string",
       "description": "Exchange-native trading pair symbol such as BTCUSDT, ETH-USD, BTC, or xyz:TSLA."
      },
      "window": {
       "enum": [
        "30m",
        "1h",
        "2h",
        "3h"
       ],
       "type": "string",
       "description": "Lookback window. Hyperliquid supports 30m and 1h; 2h and 3h are currently BTCUSDT/BTC-USD only."
      },
      "exchange": {
       "enum": [
        "binance",
        "coinbase"
       ],
       "type": "string",
       "description": "Exchange adapter to source recent trades from."
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "metric",
      "pair",
      "exchange",
      "window",
      "value",
      "computedAt",
      "tradeCount",
      "firstTradeTime",
      "lastTradeTime",
      "coverage"
     ],
     "properties": {
      "pair": {
       "type": "string"
      },
      "value": {
       "type": "number"
      },
      "metric": {
       "type": "string"
      },
      "window": {
       "enum": [
        "30m",
        "1h",
        "2h",
        "3h"
       ],
       "type": "string"
      },
      "coverage": {
       "type": "object",
       "required": [
        "requestedWindowMinutes",
        "effectiveWindowMinutes",
        "coverageRatio",
        "partialData",
        "completeFetch",
        "errorMessage"
       ],
       "properties": {
        "partialData": {
         "type": "boolean"
        },
        "errorMessage": {
         "type": [
          "string",
          "null"
         ]
        },
        "completeFetch": {
         "type": "boolean"
        },
        "coverageRatio": {
         "type": "number",
         "maximum": 1,
         "minimum": 0
        },
      
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "pair": "BTC-USD",
  "value": 3.2145,
  "metric": "roll-spread",
  "window": "30m",
  "coverage": {
   "partialData": false,
   "errorMessage": null,
   "completeFetch": true,
   "coverageRatio": 1,
   "effectiveWindowMinutes": 30,
   "requestedWindowMinutes": 30
  },
  "exchange": "coinbase",
  "components": {
   "mode": "absolute",
   "intervals": 30,
   "covariance": 2.583251,
   "observations": 28,
   "interpretation": "absolute_covariance_proxy",
   "strictRollDefined": false,
   "absoluteCovariance": 2.583251
  },
  "computedAt": "2026-05-23T14:00:00.000Z",
  "tradeCount": 428,
  "lastTradeTime": "2026-05-23T13:59:58.000Z",
  "firstTradeTime": "2026-05-23T13:00:02.000Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-dripmetrics-ai-a60c567b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.dripmetrics.ai](https://www.zero.xyz/host/api.dripmetrics.ai/llms.txt)