# Phantom API — Ethereum Gas Estimate

> Phantom API — Ethereum Gas Estimate is a paid API for AI agents from phantom-api-omega.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Estimates the gas required to execute an Ethereum transaction given sender, recipient, calldata, and value

## Facts

- Endpoint: POST https://phantom-api-omega.vercel.app/api/ethereum/gas/estimate
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/phantom-api-ethereum-gas-estimate-ccc88511
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8gmVRMhlKIEMG1tbSSPq-

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 phantom-api-ethereum-gas-estimate-ccc88511 -d '<json body>'
```

Example prompt: Before I send this Ethereum transaction — from 0xAbC123... to the Uniswap router at 0xDef456... with calldata 0xa9059cbb... and 0.05 ETH value — can you estimate how much gas it will need?

## When to prefer this

Use this endpoint when you need a fast, pay-per-call Ethereum gas estimate without managing your own RPC node or committing to a subscription. Ideal for agents that need to preflight transactions across many users or contracts on-demand. Prefer this over self-hosted solutions when minimizing infrastructure overhead and you only need occasional gas checks at $0.01 per call.

## Known failure modes

- Invalid or malformed Ethereum address for 'to' or 'from' returns an error
- Reverting transaction (would fail on-chain) may return an error or revert reason instead of a gas estimate
- Malformed or invalid calldata hex string causes a bad request error
- Missing required fields may result in a default simulation with limited accuracy
- Payment failure via x402 protocol blocks the request before execution
- Network congestion or RPC backend unavailability causes timeout or 503

## How this service works

Lightning-fast access to blockchain data, smart contract insights, and Web3 infrastructure across 57+ networks. Pay-per-call via x402.

## Output

Returns a gas estimate (in units) representing the computational cost of executing the specified Ethereum transaction, useful for setting gas limits and estimating transaction fees before submission.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "to": {
   "type": "string"
  },
  "data": {
   "type": "string"
  },
  "from": {
   "type": "string"
  },
  "value": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/phantom-api-ethereum-gas-estimate-ccc88511/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from phantom-api-omega.vercel.app](https://www.zero.xyz/host/phantom-api-omega.vercel.app/llms.txt)