# Phantom API — Monad Gas Estimator

> Phantom API — Monad 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 2026-10-20).

Estimates gas costs for transactions on the Monad blockchain network given transaction parameters

## Facts

- Endpoint: POST https://phantom-api-omega.vercel.app/api/monad/gas/estimate?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/phantom-api-monad-gas-estimator-4c890b7f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rXWj0LW_QNLeHFmi6masf

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-monad-gas-estimator-4c890b7f -d '<json body>'
```

Example prompt: Before I send this token transfer on Monad — from 0xABCD...1234 to 0xDEAD...5678 with 1 ETH worth of value — can you estimate how much gas it'll need so I know the cost upfront?

## When to prefer this

Choose this endpoint when you need gas estimation specifically on the Monad network and want pay-per-call pricing without managing your own RPC node infrastructure. Prefer over self-hosted RPC when you want zero-setup access to Monad gas data. Use when your agent workflow needs a pre-flight cost check before submitting a Monad transaction.

## Known failure modes

- Invalid or malformed address in 'to' or 'from' fields returns an error
- Malformed calldata in 'data' field causes estimation failure
- Monad network node unavailability results in timeout or 503 error
- Transactions that would revert may return estimation error or high/infinite gas estimate
- Missing required fields may return 400 bad request
- Payment not fulfilled (402) if x402 header missing or USDC balance insufficient

## 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 Monad transaction, allowing callers to predict fees and set appropriate gas limits before submission. May include estimated gas amount and optionally fee in native units.

## 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-monad-gas-estimator-4c890b7f/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)