MGO — Multi-chain Gas Optimizer

An x402-native API that compares real-time gas prices across up to 9 EVM chains and recommends the cheapest one. Built for trading agents, DeFi bots, and any AI agent that needs to optimize transaction costs.

Quick Start

# 1. Install dependencies
npm install

# 2. Set environment variables
cp .env.example .env
# Set WALLET_ADDRESS (USDC receiving wallet on Base) and CDP_API_KEY_ID/SECRET (facilitator auth)

# 3. Run locally (same entry point as production)
npm start

# 4. Test
# Open in browser: http://localhost:3000/gas/demo

Related MCP server: base-gas-mcp

Tiers

Endpoints

Payment Flow (x402 v2)

1. GET /gas/basic or /gas/premium → 402 with requirements in the PAYMENT-REQUIRED header (base64 JSON). A v1-shaped copy is also in the body for legacy clients.

2. Client signs an EIP-3009 USDC authorization on Base (eip155:8453)

3. Resend with PAYMENT-SIGNATURE header → facilitator (Coinbase CDP) verifies → data response with PAYMENT-RESPONSE receipt → USDC settled on-chain

If the upstream RPC / price feed is unavailable the API answers 503 and no payment is settled.

// Client example (@x402/fetch, x402 v2)
const { wrapFetchWithPayment } = require("@x402/fetch");
const { x402Client } = require("@x402/core/client");
const { ExactEvmScheme } = require("@x402/evm/exact/client");
const { privateKeyToAccount } = require("viem/accounts");

const client = new x402Client().register("eip155:*", new ExactEvmScheme(privateKeyToAccount(process.env.EVM_PRIVATE_KEY)));
const paidFetch = wrapFetchWithPayment(fetch, client);
const res = await paidFetch("https://api.mgo.chain-ops.xyz/gas/basic");

MCP (Claude / Cursor / any MCP client)

Remote Streamable HTTP server, no install:

{
  "mcpServers": {
    "mgo-gas": { "url": "https://api.mgo.chain-ops.xyz/mcp" }
  }
}

Also published as npm package chain-ops-mgo and in the official MCP Registry (xyz.chain-ops/mgo). Paid tools return the decoded x402 payment requirements; pay with an x402 client against the resource URL.

Operations

• Access log + /stats (Upstash Redis, key via STATS_KEY; send it as x-stats-key header)

• Demo rate limit and the CoinGecko price cache are shared through the same Redis

• Secrets never live in this repo: see .env.example

Deploy to Vercel

npm i -g vercel
vercel --prod

Platform Registration

1. BlockRun — Register MCP server URL

2. Dexter — One-line facilitator config

3. x402.org — Automatic llms.txt crawling