# Synapse API — Blockchain Gas Estimator

> Synapse API — Blockchain 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 2026-10-20).

Estimates the gas cost for a transaction on a blockchain network given transaction parameters such as sender, recipient, data payload, and value.

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/degen/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/synapse-api-blockchain-gas-estimator-6688e66f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IHm_9BPIHW-k-Px8xfwIJ

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-blockchain-gas-estimator-6688e66f -d '<json body>'
```

Example prompt: Estimate the gas needed for a transaction from 0xAbC...123 to 0xDeF...456 with a value of 0.5 ETH and this calldata: 0xa9059cbb...

## When to prefer this

Use this endpoint when you need a quick, pay-per-call gas estimate without maintaining your own blockchain node or RPC infrastructure. Ideal for agents that need to pre-check transaction costs across multiple blockchain networks before committing funds, especially in a degen/DeFi context where gas volatility matters.

## 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 unavailable or unsupported chain results in a timeout or error response
- Insufficient context (missing required fields) may return a default or zero estimate
- Rate limiting or payment failure returns a 402 Payment Required 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) for the specified transaction, allowing the caller to budget fees and decide whether to proceed with the on-chain operation.

## 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-blockchain-gas-estimator-6688e66f/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)