# Synapse API — X Layer Gas Estimator

> Synapse API — X Layer 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 2026-10-14).

Estimates the gas cost for a transaction on the X Layer (OKX Layer 2) blockchain network

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/xlayer/gas/estimate?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-x-layer-gas-estimator-394893c9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_e6azW_vvuTy2UTei3wORR

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-x-layer-gas-estimator-394893c9 -d '<json body>'
```

Example prompt: Estimate the gas needed to send 0.5 ETH from 0xAbC123... to 0xDeF456... on the X Layer network, with no calldata.

## When to prefer this

Choose this endpoint when you need to estimate gas costs specifically on the X Layer (OKX Layer 2) network before committing to a transaction. It is ideal for pre-flight checks, budgeting, and avoiding failed transactions due to insufficient gas. Use it over generic gas oracles when you need simulation-based estimates for a specific sender, recipient, and calldata combination on X Layer.

## Known failure modes

- Invalid or malformed Ethereum address in 'to' or 'from' fields returns an error
- Invalid hex-encoded 'data' field causes parsing failure
- Transaction simulation fails if the contract logic reverts, returning a revert error
- Missing required fields may return a 400 bad request
- Network unavailability or RPC issues may cause a timeout or 503 error

## 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 X Layer network, helping the caller assess cost 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-x-layer-gas-estimator-394893c9/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)