# HALOWERK kettenwerk — Smart Contract Verification

> HALOWERK kettenwerk — Smart Contract Verification is a paid API for AI agents from kette.netzhandwerker.de, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).

Verifies a smart contract on a specified EVM blockchain, returning verification status and related contract metadata.

## Facts

- Endpoint: POST https://kette.netzhandwerker.de/contract/verification
- 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-kettenwerk-smart-contract-verification-5492d634
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_byuRz8lfJNb3bPbGWMfaJ

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-kettenwerk-smart-contract-verification-5492d634 -d '<json body>'
```

Example prompt: Can you check whether the smart contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 is verified on Ethereum?

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call smart contract verification check across major EVM chains (Ethereum, Base, Arbitrum, Optimism, Polygon, BSC) without managing API keys for each block explorer separately. Ideal for agents doing pre-interaction due diligence, security audits, or investment research on specific contracts at a low cost of $0.004 per call.

## Known failure modes

- Invalid contract address format (must be 0x-prefixed 40 hex chars) — returns 400 or validation error
- Contract address not found on specified chain — returns not-found or unverified status
- Unsupported chain specified — returns error if chain not in enum
- Payment failure via x402 protocol — call not executed if USDC micropayment on Base Mainnet fails
- Network/upstream explorer timeout — may return 503 or empty result if block explorer is unavailable

## How this service works

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

## Output

Returns the verification status of the specified smart contract on the chosen EVM chain, typically including whether the contract is verified, its source code availability, compiler details, and related metadata about the deployment.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "chain": {
   "enum": [
    "ethereum",
    "base",
    "arbitrum",
    "optimism",
    "polygon",
    "bsc"
   ],
   "type": "string",
   "description": "Chain the contract lives on."
  },
  "address": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]{40}$",
   "description": "Contract address."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-kettenwerk-smart-contract-verification-5492d634/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from kette.netzhandwerker.de](https://www.zero.xyz/host/kette.netzhandwerker.de/llms.txt)