Skill: bryan-cmc/cmc-x402 (version 1.0.1)

--- name: cmc-x402 description: | Access CoinMarketCap data via x402 pay-per-request protocol with USDC payments on Base. Use when users mention x402, want CMC data without API keys, ask about pay-per-request APIs, or need to integrate CMC with on-chain payments. Also use for any Coinbase x402 protocol questions. Trigger: "x402", "pay per request", "no API key", "USDC payment", "CMC without subscription", "/cmc-x402" homepage: https://github.com/coinmarketcap/skills-for-ai-agents-by-CoinMarketCap source: https://github.com/coinmarketcap/skills-for-ai-agents-by-CoinMarketCap user-invocable: true --- # 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 ($0.01 per request) 4. **Small amount of ETH on Base** for gas fees ## Use Cases **Get current prices for specific coins:** Use [REDACTED_SECRET] with symbol or id parameter. Example: Get BTC and ETH prices for a portfolio tracker. **List top cryptocurrencies:** Use [REDACTED_SECRET] with limit parameter. Example: Display top 100 coins ranked by market cap. **Search for DEX tokens:** Use `/x402/v1/dex/search` with keyword parameter. Example: Find a memecoin by name when you don't know the contract address. **Get DEX pair trading data:** Use [REDACTED_SECRET] with pair address. Example: Monitor liquidity and volume for a specific Uniswap pool. **AI agent data access:** Use the MCP endpoint at `https://mcp.coinmarketcap.com/x402/mcp`. Example: Let Claude or other LLMs fetch live crypto data with automatic payment. ## Quick Start Install the x402 TypeScript SDK: ```bash npm install @x402/axios @x402/evm viem ``` Fetch data with automatic payment: ```typescript import { createX402AxiosClient } from "@x402/axios"; import { ExactEvmScheme, toClientEvmSigner } from "@x402/evm"; import { privateKeyToAccount } from "viem/accounts"; import { createPublicClient, http } from "viem"; import { base } from "viem/chains"; // SECURITY: Never hardcode private keys in source code. // Use environment variables: process.env.PRIVATE_KEY // For production, use a dedicated hot wallet with limited funds. const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${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` | Endpoint | Path | Use For | |----------|------|---------| | Quotes | [REDACTED_SECRET] | Current prices for specific coins | | Listings | [REDACTED_SECRET] | Top coins by market cap | | DEX Search | `/x402/v1/dex/search` | Find DEX tokens by keyword | | DEX Pairs | [REDACTED_SECRET] | DEX pair trading data | All parameters from the standard CMC Pro API work with x402 endpoints. See [endpoints.md](references/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 - [endpoints.md](references/endpoints.md) - Full parameter reference for all endpoints - [payment-details.md](references/payment-details.md) - 402 response format, contract addresses, manual integration ## Resources - x402 Protocol: https://x402.org - x402 Documentation: https://docs.x402.org - x402 GitHub: https://github.com/coinbase/x402 - CMC API Documentation: https://coinmarketcap.com/api/documentation


Security scan verdicts — ClawScan: suspicious | static analysis: clean | VirusTotal: clean | SkillSpector: clean (LOW)