OpenSkillIndex← back to search
claude-codeopenclawfinance

Skills cmc-x402

install
source · Clone the upstream repo
git clone https://github.com/openclaw/skills
Claude Code · Install into ~/.claude/skills/
T=$(mktemp -d) && git clone --depth=1 https://github.com/openclaw/skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/bryan-cmc/cmc-x402" ~/.claude/skills/openclaw-skills-cmc-x402 && rm -rf "$T"
OpenClaw · Install into ~/.openclaw/skills/
T=$(mktemp -d) && git clone --depth=1 https://github.com/openclaw/skills "$T" && mkdir -p ~/.openclaw/skills && cp -r "$T/skills/bryan-cmc/cmc-x402" ~/.openclaw/skills/openclaw-skills-cmc-x402 && rm -rf "$T"
manifest: skills/bryan-cmc/cmc-x402/SKILL.md
tags
#crypto#coinmarketcap#x402#payment#api
source content

CoinMarketCap x402

Pay-per-request crypto market data powered by the x402 protocol. Access CoinMarketCap endpoints instantly with on-chain USDC payment. No API key or subscription required.

What is x402?

x402 is an open payment protocol developed by Coinbase that enables automatic stablecoin payments over HTTP. Instead of managing API keys, you pay $0.01 USDC per request on Base. The x402 client library handles payment signing automatically.

Learn more: https://docs.x402.org

Prerequisites

Before using x402 endpoints, ensure you have:

  1. Node.js 18+ and npm installed
  2. Base network wallet with a private key you control
  3. USDC on Base to pay for requests ($0.01 per request)
  4. Small amount of ETH on Base for gas fees

Use Cases

Get current prices for specific coins: Use 

/x402/v3/cryptocurrency/quotes/latest
with symbol or id parameter. Example: Get BTC and ETH prices for a portfolio tracker.

List top cryptocurrencies: Use 

/x402/v3/cryptocurrency/listing/latest
with limit parameter. Example: Display top 100 coins ranked by market cap.

Search for DEX tokens: Use 

/x402/v1/dex/search
with keyword parameter. Example: Find a memecoin by name when you don't know the contract address.

Get DEX pair trading data: Use 

/x402/v4/dex/pairs/quotes/latest
with pair address. Example: Monitor liquidity and volume for a specific Uniswap pool.

AI agent data access: Use the MCP endpoint at 

https://mcp.coinmarketcap.com/x402/mcp
. Example: Let Claude or other LLMs fetch live crypto data with automatic payment.

Quick Start

Install the x402 TypeScript SDK:

npm install @x402/axios @x402/evm viem

Fetch data with automatic payment:

import { createX402AxiosClient } from "@x402/axios";
import { ExactEvmScheme, toClientEvmSigner } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";
import { createPublicClient, http } from "viem";
import { base } from "viem/chains";

// SECURITY: Never hardcode private keys in source code.
// Use environment variables: process.env.PRIVATE_KEY
// For production, use a dedicated hot wallet with limited funds.
const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
const publicClient = createPublicClient({ chain: base, transport: http() });
const signer = toClientEvmSigner(account, publicClient);

const client = createX402AxiosClient({
  schemes: [new ExactEvmScheme(signer)],
});

const response = await client.get(
  "https://pro.coinmarketcap.com/x402/v3/cryptocurrency/quotes/latest",
  { params: { symbol: "BTC,ETH" } }
);

console.log(response.data);

Endpoints

Base URL: 

https://pro.coinmarketcap.com

EndpointPathUse For
Quotes
/x402/v3/cryptocurrency/quotes/latest
Current prices for specific coins
Listings
/x402/v3/cryptocurrency/listing/latest
Top coins by market cap
DEX Search
/x402/v1/dex/search
Find DEX tokens by keyword
DEX Pairs
/x402/v4/dex/pairs/quotes/latest
DEX pair trading data

All parameters from the standard CMC Pro API work with x402 endpoints. See endpoints.md for full parameter reference.

MCP for AI Agents

The x402 MCP endpoint lets AI agents access CMC data with automatic payment.

Connection URL:

https://mcp.coinmarketcap.com/x402/mcp

Transport: Streamable HTTP (POST)

Connect using any MCP client with an x402-aware HTTP transport. The server exposes the same tools as the REST endpoints and supports automatic tool discovery.

Pricing

$0.01 USDC per request on Base (Chain ID: 8453).

Payment only occurs on successful data delivery. If the request fails, no payment is deducted.

References

Resources