# HALOWERK marktwerk Open Interest Change

> HALOWERK marktwerk Open Interest Change is a paid API for AI agents from markt.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Compares current open interest on Binance USDⓈ-M Futures perpetuals against the value at the start of a configurable window, alongside price and volume changes, with a built-in interpretation rule.

## Facts

- Endpoint: POST https://markt.halowerk.com/open-interest
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-marktwerk-open-interest-change-881ffd73
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_l95xBhB5IgicfHxu-pm4x

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-open-interest-change-881ffd73 -d '<json body>'
```

Example prompt: What's the open interest change for BTC/USDT on Binance futures over the last 4 hours, and is the move trend-confirmed or a divergence?

## When to prefer this

Choose this endpoint when you need a self-consistent open interest comparison — both baseline and current values come from the same recording source, so there is no cross-venue basis mismatch. Prefer it when you want price, volume, and OI changes over an identical window with a deterministic interpretation rule, rather than raw ticker data or multi-exchange aggregation. Best for derivatives-focused agents that need structured trend signals on Binance USDⓈ-M Futures perpetuals.

## Known failure modes

- Unsupported symbol pattern returns validation error
- Venue other than binance-futures is rejected (only one supported)
- Symbol not listed on Binance USDⓈ-M Futures returns not-found or empty result
- Window outside allowed enum values (1h, 4h, 24h) causes schema rejection
- Stale or missing candle data may produce gaps if exchange data is unavailable
- Payment failure via x402 protocol blocks access

## How this service works

Compares the open interest recorded now with the value this hub recorded itself at the start of the window, so both numbers come from the same source and the same basis. Notional value is always taken with the price of its own point in time, never recomputed with the current price. price_change_pct and volume_change_pct cover exactly the same window from the recorded minute candles. interpretation follows a rule printed in the answer, so a buyer can recompute it: price and open interest rising t

## Output

Returns the open interest at the window start and the current open interest (both in notional USD and contract units, priced at their respective point-in-time prices), percentage change in open interest, percentage change in price, percentage change in volume over the same window, and a rule-based interpretation string (e.g. 'price up, OI up → trend continuation') that can be independently verified.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "symbol": {
   "type": "string",
   "pattern": "^[A-Za-z0-9]{2,15}/[A-Za-z0-9]{2,15}$",
   "description": "Perpetual as BASE/QUOTE, for example BTC/USDT."
  },
  "venues": {
   "type": "array",
   "items": {
    "enum": [
     "binance-futures"
    ],
    "type": "string"
   },
   "maxItems": 1,
   "minItems": 1,
   "description": "Venues whose open interest this hub records. Only Binance USDⓈ-M Futures is recorded so far.",
   "uniqueItems": true
  },
  "window": {
   "enum": [
    "1h",
    "4h",
    "24h"
   ],
   "type": "string",
   "default": "1h",
   "description": "Comparison window."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-marktwerk-open-interest-change-881ffd73/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)