# Ethereum Gas Estimator (agentshelf.syntexa.ch)

> Ethereum Gas Estimator (agentshelf.syntexa.ch) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-20).

Estimates gas usage, current gas price, and total transaction cost in ETH and USD for an Ethereum mainnet transaction.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/eth-estimate-gas?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ethereum-gas-estimator-agentshelf-syntexa-ch-184a3b59
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RvM9FwyU9wSnme6eLsPMH

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 ethereum-gas-estimator-agentshelf-syntexa-ch-184a3b59 -d '<json body>'
```

Example prompt: How much will it cost in ETH and USD to send a transaction to 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Ethereum mainnet right now? Give me the gas estimate and current gas price.

## When to prefer this

Use this endpoint when you need a quick, read-only gas estimate for an Ethereum mainnet transaction without executing it. Ideal for pre-flight cost checks before submitting a transaction, or when you need both ETH and USD cost breakdowns without building your own RPC integration. The sandbox endpoint at /v1/sandbox/eth-estimate-gas is free to try before paying $0.003 USDC per live call.

## Known failure modes

- Invalid or missing 'to' address when 'data' is also absent — returns validation error
- Malformed hex in 'data' field (odd-length or non-hex characters) — returns bad request
- Transaction would revert on-chain (e.g. contract reverts) — gas estimation fails with revert error
- Ethereum node unavailable or rate-limited — returns 503 or timeout
- Payment not included or insufficient USDC on Base — returns 402 Payment Required; sandbox endpoint available for free testing

## How this service works

Call when an agent needs eth_estimateGas, the current gas price, and the estimated cost in ETH and USD for an Ethereum transaction. Send to and optional from, data, and value. Read-only. No spend. Send JSON {"to":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"}. Exact $0.003 USDC on Base. Try unpaid POST /v1/sandbox/eth-estimate-gas first.

## Output

Returns the estimated gas units (eth_estimateGas result), the current network gas price in wei or gwei, and the total estimated transaction cost expressed in both ETH and USD at the current price.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "to": {
   "type": "string",
   "examples": [
    "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
   ],
   "description": "Optional recipient or contract on Ethereum mainnet. Example: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045. Required when data is omitted."
  },
  "data": {
   "type": "string",
   "maxLength": 2048,
   "description": "Optional calldata, even-length 0x hex, at most 2048 characters. Example: 0x. Required when to is omitted."
  },
  "from": {
   "type": "string",
   "description": "Optional sender on Ethereum mainnet. Example: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045. EIP-55 or all one case. Read-only."
  },
  "value": {
   "type": "string",
   "description": "Optional value in wei, as a decimal integer or 0x hex quantity. Example: 0. Omit it for zero."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ethereum-gas-estimator-agentshelf-syntexa-ch-184a3b59/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)