# Synapse API — Worldchain Gas Estimator

> Synapse API — Worldchain 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 Worldchain blockchain network before submission

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/worldchain/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-worldchain-gas-estimator-4822acd0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5riO3YGNNZwshoEtmM8lM

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-worldchain-gas-estimator-4822acd0 -d '<json body>'
```

Example prompt: Estimate the gas cost for a Worldchain transaction from 0xAbcD...1234 to 0x5678...EfGh with a value of 0.01 ETH and this calldata: 0xd0e30c0b.

## When to prefer this

Choose this endpoint when you need a gas estimate specifically on the Worldchain network before committing to a transaction. It is ideal for pre-flight checks in DeFi workflows, NFT mints, or any smart contract interaction on Worldchain where cost predictability matters before signing and broadcasting.

## Known failure modes

- Invalid address format in 'to' or 'from' fields returns a validation error
- Malformed or invalid 'data' hex string causes a parsing error
- Transaction simulation failure if the contract reverts during estimation
- Network congestion or RPC node unavailability may cause timeouts
- Missing required fields may return a 400 bad request

## 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 gas estimate (in gas units) for the proposed transaction on the Worldchain network, allowing the caller to understand expected fees before 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-worldchain-gas-estimator-4822acd0/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)