# Synapse API — Robinhood Gas Estimator

> Synapse API — Robinhood 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 fees for an EVM transaction given sender, recipient, calldata, and value fields

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/robinhood/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-robinhood-gas-estimator-efe40845
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_n7uBYsJlYlfinV4mKprym

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-robinhood-gas-estimator-efe40845 -d '<json body>'
```

Example prompt: Can you estimate the gas cost for sending 0.5 ETH from 0xAbC...123 to 0xDeF...456 with no calldata, so I know the fee before I submit the transaction?

## When to prefer this

Use this endpoint when you need a quick, pay-per-call gas estimate for an EVM transaction without running your own node or RPC infrastructure. Ideal for agents automating blockchain interactions that need to budget gas costs before submitting transactions, especially when you want a simple REST API interface rather than direct RPC eth_estimateGas calls.

## Known failure modes

- Invalid or malformed address in 'to' or 'from' fields returns an error
- Malformed or non-hex 'data' field causes parsing failure
- Network unavailability or RPC node timeout may produce errors or stale estimates
- Missing required fields may return a validation error
- Gas estimation may fail if the simulated transaction would revert on-chain

## 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 a computed gas estimate (in gas units) for the described EVM transaction, allowing the caller to predict fees and set appropriate gas limits before broadcasting on-chain.

## 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-robinhood-gas-estimator-efe40845/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)