# Synapse API — Arbitrum Gas Estimator

> Synapse API — Arbitrum 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 the gas cost for a transaction on the Arbitrum network given sender, recipient, calldata, and value

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/arbitrum/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-arbitrum-gas-estimator-deeb34e0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JAYnI8mWu1kv0LlolUGZ1

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-arbitrum-gas-estimator-deeb34e0 -d '<json body>'
```

Example prompt: Estimate the gas needed for an Arbitrum transaction from 0xSenderAddress to 0xContractAddress with calldata 0xabcdef and a value of 0 ETH.

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call gas estimate for Arbitrum specifically, without managing your own RPC node or paying for a full node subscription. It is ideal for agents that need pre-flight cost checks before executing L2 transactions on Arbitrum.

## Known failure modes

- Invalid or malformed address in 'to' or 'from' fields returns an error
- Invalid calldata hex string causes a parse or simulation error
- Simulation reverts if the transaction would fail on-chain (e.g., insufficient balance or bad contract call)
- Missing required fields may return a 400 bad request
- Network congestion or RPC issues may cause timeout or degraded accuracy

## 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 value (in gas units) for the described Arbitrum transaction, allowing callers to anticipate fees before broadcasting to the network.

## 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-arbitrum-gas-estimator-deeb34e0/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)