# HALOWERK kettenwerk Gas Fee API

> HALOWERK kettenwerk Gas Fee API is a paid API for AI agents from kette.netzhandwerker.de, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).

Returns current gas fees and estimated transaction costs for a specified EVM-compatible blockchain and transaction type

## Facts

- Endpoint: POST https://kette.netzhandwerker.de/gas
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-kettenwerk-gas-fee-api-36202502
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QV3HRoeovmalgL6JXtTCT

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-gas-fee-api-36202502 -d '<json body>'
```

Example prompt: What are the current gas fees on Arbitrum for an ERC-20 transfer — show me all three speed tiers so I can decide whether to go slow or fast?

## When to prefer this

Choose this endpoint when you need real-time gas fee estimates across major EVM chains (Ethereum, Base, Arbitrum, Optimism, Polygon, BSC) broken down by transaction type (native transfer, ERC-20, swap, NFT mint, contract deploy). Particularly useful when an agent needs to estimate costs before submitting an on-chain transaction or when comparing fees across networks. The per-transaction pricing via x402/USDC makes it suitable for pay-as-you-go agent workflows without subscription overhead.

## Known failure modes

- Unsupported chain value returns validation error
- Invalid speed or tx_type enum returns 400 bad request
- Payment failure or insufficient USDC balance returns 402
- Network congestion may cause stale or delayed fee data
- Chain RPC node unavailability may cause 503 or timeout

## How this service works

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

## Output

Returns gas fee data for the requested EVM chain across all three speed tiers (slow/normal/fast), along with a total cost estimate in native token and USD for the specified transaction type profile, including the assumed gas limit and calldata byte size used in the calculation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "chain": {
   "enum": [
    "ethereum",
    "base",
    "arbitrum",
    "optimism",
    "polygon",
    "bsc"
   ],
   "type": "string",
   "description": "Chain to read fees from."
  },
  "speed": {
   "enum": [
    "langsam",
    "normal",
    "schnell",
    "alle"
   ],
   "type": "string",
   "default": "alle",
   "description": "Which speed level to highlight. All three are always returned."
  },
  "tx_type": {
   "enum": [
    "native_transfer",
    "erc20_transfer",
    "erc20_approve",
    "swap",
    "nft_mint",
    "contract_deploy"
   ],
   "type": "string",
   "default": "erc20_transfer",
   "description": "Transaction profile used for the total cost estimate. Its assumed gas limit and byte size are stated in the answer."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-kettenwerk-gas-fee-api-36202502/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)