# Phantom API — Unichain Gas Estimator

> Phantom API — Unichain Gas Estimator 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 cost of a transaction on the Unichain network before sending it

## Facts

- Endpoint: POST https://phantom-api-omega.vercel.app/api/unichain/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-unichain-gas-estimator-1b5d40ab
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4nM3Su69qJB48v_zPSYdn

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-unichain-gas-estimator-1b5d40ab -d '<json body>'
```

Example prompt: Estimate the gas for a Unichain transaction from 0xAbC...123 to the contract at 0xDeF...456 with calldata 0xa9059cbb... and a value of 0 ETH.

## When to prefer this

Choose this endpoint when you specifically need to estimate gas on the Unichain network prior to submitting a transaction. It is ideal for agents that need to budget transaction costs, validate transaction feasibility, or decide whether to proceed with an on-chain action without incurring actual gas spend. Prefer this over general EVM gas estimators when your target chain is Unichain.

## Known failure modes

- Invalid or malformed address in 'to' or 'from' fields — returns a 400 or RPC error
- Reverted simulation — if the transaction would revert on-chain, the estimate call may fail with a revert reason
- Missing required fields — omitting 'to' without providing 'data' for a deployment may cause errors
- Network unavailability — Unichain RPC node downtime returns a 502 or timeout
- Payment failure — if x402 payment is not included or is insufficient, returns a 402 Payment Required

## 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 gas units) for the described transaction on Unichain, allowing the caller to predict cost before broadcasting the transaction to the network.

## 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-unichain-gas-estimator-1b5d40ab/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)