# HALOWERK marktwerk Open Interest

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

Returns open interest data for a perpetual futures trading pair on Binance USDⓈ-M Futures, with comparison over a configurable time window.

## Facts

- Endpoint: POST https://markt.netzhandwerker.de/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-9f17931b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GOIgXINR_o0QeCbx-F66Q

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-9f17931b -d '<json body>'
```

Example prompt: What's the open interest for BTC/USDT on Binance futures right now, and how has it changed over the last 4 hours?

## When to prefer this

Use this endpoint when you need open interest data specifically for Binance USDⓈ-M perpetual futures with windowed comparison (1h, 4h, 24h). Prefer it for lightweight, pay-per-call access to derivatives market metrics without managing a Binance API key or WebSocket connection. Best suited for agents making infrequent or triggered lookups rather than continuous streaming.

## Known failure modes

- Invalid symbol format not matching BASE/QUOTE pattern returns validation error
- Unsupported venue (only binance-futures is currently available)
- Symbol not listed on Binance USDⓈ-M Futures returns not-found or empty result
- Payment failure via x402/USDC causes 402 response and no data
- Network timeout from upstream Binance data source

## How this service works

HALOWERK marktwerk — bezahlte Endpunkte nach x402. Preise in USDC auf Base Mainnet.

## Output

Returns current open interest figures for the specified perpetual futures symbol on Binance USDⓈ-M Futures, along with a comparison showing how open interest has changed over the requested window (1h, 4h, or 24h).

## 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-9f17931b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from markt.netzhandwerker.de](https://www.zero.xyz/host/markt.netzhandwerker.de/llms.txt)