# HALOWERK marktwerk Volume Anomaly Detector

> HALOWERK marktwerk Volume Anomaly Detector is a paid API for AI agents from markt.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-12).

Detects statistically anomalous trading volumes by comparing the latest completed minute candle against a configurable historical baseline using robust median/MAD statistics

## Facts

- Endpoint: POST https://markt.halowerk.com/anomaly/volume?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-marktwerk-volume-anomaly-detector-d99e87af
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XNS5zt02NLcCjWwAGuznx

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 halowerk-marktwerk-volume-anomaly-detector-d99e87af -d '<json body>'
```

Example prompt: Check Binance for any unusual volume spikes on BTC/USDT, ETH/USDT, and SOL/USDT over the last 24 hours using normal sensitivity — flag anything with a statistically significant z-score.

## When to prefer this

Choose this endpoint when you need robust, outlier-resistant volume anomaly detection using median/MAD statistics rather than mean/std, especially for skewed crypto volume distributions. It is self-contained — no external price feed needed — because the hub records its own history every minute. Prefer it over raw candle endpoints when you want pre-computed statistical significance scores rather than raw OHLCV data, and over general-purpose stats APIs when you want crypto-specific multi-venue coverage with configurable sensitivity thresholds.

## Known failure modes

- Requested symbol not in watched_pairs — pair is not tracked by this hub's collector, returns no finding
- Insufficient history for the chosen lookback window — not enough samples to compute reliable MAD baseline
- Invalid symbol format — must match BASE/QUOTE pattern with 2-15 alphanumeric characters per side
- Unsupported venue — only binance, coinbase, kraken, okx, bybit are accepted
- Payment failure — x402 payment of 0.003 USDC not fulfilled, request rejected
- Too many symbols — maxItems is 20, requests exceeding this are rejected

## How this service works

Compares the volume of the most recent completed minute candle with the distribution of minute volumes over the chosen lookback, taken from the history this hub records itself every minute. Median and median absolute deviation are used instead of mean and standard deviation because volume is skewed. Every finding carries its z value, the baseline median, the baseline MAD and the number of samples behind it, so it can be recomputed rather than believed. Pairs without a finding are returned in qui

## Output

Returns a list of pairs that triggered an anomaly finding, each with its robust z-score, baseline median volume, median absolute deviation, and sample count so results can be independently verified. Pairs with no anomaly are returned in a quiet list. The response also includes a watched_pairs field listing which symbols the hub tracks.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "venue": {
   "enum": [
    "binance",
    "coinbase",
    "kraken",
    "okx",
    "bybit"
   ],
   "type": "string",
   "default": "binance",
   "description": "Exchange whose recorded history is used."
  },
  "symbols": {
   "type": "array",
   "items": {
    "type": "string",
    "pattern": "^[A-Za-z0-9]{2,15}/[A-Za-z0-9]{2,15}$"
   },
   "maxItems": 20,
   "minItems": 1,
   "description": "Pairs as BASE/QUOTE. Only pairs the collector of this hub watches can be answered; watched_pairs in the answer lists them.",
   "uniqueItems": true
  },
  "lookback": {
   "enum": [
    "1h",
    "4h",
    "24h",
    "7d"
   ],
   "type": "string",
   "default": "24h",
   "description": "Length of the baseline window."
  },
  "sensitivity": {
   "enum": [
    "streng",
    "normal",
    "weit"
   ],
   "type": "string",
   "default": "normal",
   "description": "Threshold on the robust z value: streng 5, normal 3.5, weit 2.5."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-marktwerk-volume-anomaly-detector-d99e87af/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from markt.halowerk.com](https://www.zero.xyz/host/markt.halowerk.com/llms.txt)