# HALOWERK defiwerk Oracle Crosscheck

> HALOWERK defiwerk Oracle Crosscheck is a paid API for AI agents from defi.netzhandwerker.de, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).

Aggregates and cross-checks crypto asset prices from multiple oracle sources (Chainlink, Pyth, RedStone, CEX, DEX spot/TWAP) across major EVM chains

## Facts

- Endpoint: POST https://defi.netzhandwerker.de/oracle/crosscheck
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-defiwerk-oracle-crosscheck-910fb4fb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_X9EyKQ1vZqkU-svWhIOJT

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-defiwerk-oracle-crosscheck-910fb4fb -d '<json body>'
```

Example prompt: Cross-check the current ETH price on Base using all available oracle sources — Chainlink, Pyth, RedStone, CEX, and DEX spot — and show me how they compare.

## When to prefer this

Use this endpoint when you need to cross-validate crypto asset prices across multiple oracle sources rather than trusting a single feed. Ideal for DeFi risk management, arbitrage detection, oracle manipulation checks, and pre-trade sanity checks. Prefer this over single-oracle price feeds when price integrity and multi-source consensus matter. Best suited for Base, Ethereum, Arbitrum, Optimism, and Polygon for the supported assets (ETH, BTC, USDC, USDT, DAI, LINK, CBETH, AERO).

## Known failure modes

- Asset not supported on the specified chain — returns error indicating unavailability
- Oracle source type not available for the given asset/chain combination
- Payment failure via x402 — endpoint returns 402 if USDC payment on Base Mainnet is not provided or insufficient
- Invalid asset or chain enum value — request rejected with validation error
- Network or RPC issues causing on-chain source reads to fail

## How this service works

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

## Output

Returns price readings for the requested asset from multiple oracle sources (e.g. Chainlink, Pyth, RedStone, CEX reference price, DEX spot, DEX TWAP) on the specified chain, allowing comparison and cross-validation of price data across sources.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "asset": {
   "enum": [
    "ETH",
    "BTC",
    "USDC",
    "USDT",
    "DAI",
    "LINK",
    "CBETH",
    "AERO"
   ],
   "type": "string",
   "description": "Asset symbol. Only assets whose sources were individually verified against the chain are available."
  },
  "chain": {
   "enum": [
    "base",
    "ethereum",
    "arbitrum",
    "optimism",
    "polygon"
   ],
   "type": "string",
   "description": "Chain the on-chain sources are read from. Off-chain sources are chain independent."
  },
  "oracles": {
   "type": "array",
   "items": {
    "enum": [
     "chainlink",
     "pyth",
     "redstone",
     "cex",
     "dex_spot",
     "dex_twap"
    ],
    "type": "string"
   },
   "description": "Optional filter for source types. Omitted means all available types."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-defiwerk-oracle-crosscheck-910fb4fb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from defi.netzhandwerker.de](https://www.zero.xyz/host/defi.netzhandwerker.de/llms.txt)