# HALOWERK kettenwerk – EVM Transaction Simulator

> HALOWERK kettenwerk – EVM Transaction Simulator is a paid API for AI agents from kette.netzhandwerker.de, paid per call via x402, $0.012/call, status unknown (last checked 2026-09-15).

Simulates an EVM transaction on a specified chain and block without broadcasting it, returning execution results and state changes.

## Facts

- Endpoint: POST https://kette.netzhandwerker.de/tx/simulate
- Price: $0.012/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-kettenwerk-evm-transaction-simulator-3f730ac3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WGkPBR5Q4ONClRXm4_Ilj

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-evm-transaction-simulator-3f730ac3 -d '<json body>'
```

Example prompt: Simulate a call to the Uniswap v3 router on Ethereum mainnet — sender 0xAbCd...1234, target 0xE592427A0AEce92De3Edee1F18E0157C05861564, calldata 0x414bf389..., value 0, using the latest block — and tell me if it would succeed or revert.

## When to prefer this

Choose this endpoint when you need to simulate a raw EVM transaction across Ethereum, Base, Arbitrum, Optimism, Polygon, or BSC with optional state overrides — particularly useful for pre-flight validation, debugging reverts, or replaying historical transactions. Prefer this over general RPC providers when you want a simple HTTP POST API with per-call micropayment billing (x402/USDC) rather than managing your own node or RPC credentials.

## Known failure modes

- Invalid Ethereum address format for 'from' or 'to' → validation error
- Unsupported chain value → enum validation failure
- Gas limit below 21000 or above 30000000 → rejected
- Malformed calldata (not valid hex) → parse error
- Block number not found on the target chain → simulation error
- Node unavailable for the requested chain → 503 or timeout
- Insufficient payment (x402 payment missing or wrong amount) → 402 Payment Required

## How this service works

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

## Output

Returns the outcome of the simulated EVM transaction including success/failure status, gas consumed, return data, revert reason (if applicable), and any state changes — without broadcasting anything to the network.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "to": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]{40}$",
   "description": "Target address."
  },
  "gas": {
   "type": "integer",
   "maximum": 30000000,
   "minimum": 21000,
   "description": "Optional gas limit for the simulation."
  },
  "data": {
   "type": "string",
   "default": "0x",
   "pattern": "^0x[0-9a-fA-F]*$",
   "description": "Call data."
  },
  "from": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]{40}$",
   "description": "Sender address. No signature is needed and none is created."
  },
  "block": {
   "type": "string",
   "default": "latest",
   "description": "\"latest\" or a block number as decimal string."
  },
  "chain": {
   "enum": [
    "ethereum",
    "base",
    "arbitrum",
    "optimism",
    "polygon",
    "bsc"
   ],
   "type": "string",
   "description": "Chain to simulate on."
  },
  "value": {
   "type": "string",
   "default": "0",
   "description": "Value in wei, decimal or 0x."
  },
  "state_overrides": {
   "type": "object",
   "description": "Optional state overrides per address, in the eth_simulateV1 format (balance, nonce, code, state, stateDiff)."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-kettenwerk-evm-transaction-simulator-3f730ac3/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)