# Synapse API — Blockchain Gas Estimation

> Synapse API — Blockchain Gas Estimation 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 2026-09-16).

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

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/adi/gas/estimate
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-blockchain-gas-estimation-43afd211
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RjG7DdfGly6x4mYSrGYqZ

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-estimation-43afd211 -d '<json body>'
```

Example prompt: Estimate the gas cost for a transaction from 0xABC...123 to 0xDEF...456 with no calldata and a value of 0.1 ETH.

## When to prefer this

Use this endpoint when you need a quick, pay-per-call gas estimate for a blockchain transaction without setting up your own RPC node or provider credentials. Particularly useful for agents that need to budget transaction costs across multiple chains before committing to a send.

## Known failure modes

- Invalid or malformed address in 'to' or 'from' fields returns an error
- Malformed hex in 'data' field causes parse error
- Network or RPC unavailability may cause timeout or 503
- Missing required fields may return 400 bad request
- Estimate may be inaccurate if blockchain state changes between estimate and actual submission

## 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 (and potentially estimated fee in native currency) required to execute the described transaction, allowing the caller to budget fees before submitting the transaction 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-blockchain-gas-estimation-43afd211/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)