# DripMetrics VPIN (Volume-Synchronized Probability of Informed Trading)

> DripMetrics VPIN (Volume-Synchronized Probability of Informed Trading) is a paid API for AI agents from api.dripmetrics.ai, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-10).

Computes VPIN, a measure of the probability of informed trading, for a specified crypto trading pair and exchange over a recent lookback window.

## Facts

- Endpoint: GET https://api.dripmetrics.ai/metrics/vpin?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-dripmetrics-ai-c7aab742
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_blZ0kzaNl9-ciNDQ8TocP

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-c7aab742
```

Example prompt: What's the current VPIN for BTCUSDT on Binance over the last 1 hour — I want to know how much informed trading activity is happening right now.

## When to prefer this

Use this endpoint when you need a real-time, volume-clock-based informed trading probability signal for a specific crypto pair on Binance or Coinbase — particularly useful for detecting toxic order flow, assessing adverse selection risk before placing large orders, or building microstructure-aware trading strategies. Prefer this over simpler spread or volume metrics when you need a theoretically grounded, academically recognized measure of information asymmetry.

## Known failure modes

- Unsupported exchange name returns an error (only 'binance' or 'coinbase' accepted)
- Unsupported window value returns an error (only '30m' or '1h' accepted)
- Invalid or unrecognized pair symbol returns an error or empty result
- Insufficient trade data in the window may result in a low tradeCount or computation error
- Payment failure (x402) if USDC balance is insufficient blocks the request

## 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 JSON object with the VPIN scalar value (0–1 probability), the trading pair, exchange, window, computation timestamp, trade count, first and last trade timestamps, and breakdown components (bucket count, bucket size, total volume, mean imbalance).

## 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",
        "hyperliquid"
       ],
       "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,
         "minimu
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "pair": "BTC-USD",
  "value": 0.18624412,
  "metric": "vpin",
  "window": "30m",
  "coverage": {
   "partialData": false,
   "errorMessage": null,
   "completeFetch": true,
   "coverageRatio": 1,
   "effectiveWindowMinutes": 30,
   "requestedWindowMinutes": 30
  },
  "exchange": "coinbase",
  "components": {
   "buckets": 20,
   "bucketSize": 12.842913,
   "totalVolume": 256.85826,
   "meanImbalance": 2.392118
  },
  "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-c7aab742/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)