# Synapse API — Metis Gas Estimator

> Synapse API — Metis Gas Estimator is a paid API for AI agents from synapse-api-brown.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Estimates gas costs for a transaction on the Metis blockchain network given sender, recipient, calldata, and value

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/metis/gas/estimate
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-metis-gas-estimator-12a3ee6c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vhZKvSsLlo07deBIeegk7

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 synapse-api-metis-gas-estimator-12a3ee6c -d '<json body>'
```

Example prompt: Estimate the gas cost for a Metis transaction from 0xAbC...123 to 0xDeF...456 with calldata 0xa9059cbb000000000000000000000000... and a value of 0.

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call gas estimate specifically for the Metis (layer 2) network without managing your own RPC infrastructure. Ideal for agents or wallets that need pre-flight cost checks before submitting transactions on Metis, especially when supporting 57+ blockchain networks through the same API suite is a requirement.

## Known failure modes

- Invalid or malformed Ethereum address for 'to' or 'from' fields returns an error
- Invalid hex-encoded calldata in 'data' field causes estimation failure
- Metis RPC node unavailability results in a timeout or service error
- Transactions that would revert on-chain may return an error or unreliable estimate
- Missing required fields may result in a 400 bad request response

## How this service works

High-speed API suite for AI processing, web scraping, and smart data utilities across 57+ blockchain networks. Pay-per-call via x402.

## Output

Returns an estimated gas amount (in gas units) required to execute the specified transaction on the Metis network, allowing the caller to budget fees and decide whether to proceed before actually broadcasting the transaction.

## 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/synapse-api-metis-gas-estimator-12a3ee6c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from synapse-api-brown.vercel.app](https://www.zero.xyz/host/synapse-api-brown.vercel.app/llms.txt)