How to Install send21 in Windsurf

Crypto pay links and API for people and AI agents.

What send21 does

send21 creates crypto pay links, payment requests and invoices for people and AI agents. It's non-custodial: send21 never holds funds or keys and never signs or broadcasts; the payer signs from their own wallet. Supports BTC (on-chain and Lightning), USDC, USDT, EURC, SOL and ETH on Bitcoin, Solana, Ethereum, Base, Arbitrum and Polygon, priced in crypto or any of 161 fiat currencies. Hosted MCP server (Streamable HTTP) with 14 tools at https://send21.io/mcp; authenticate with an s21_ API key from https://send21.io/api-keys as a bearer token, or sign in with OAuth. API keys can only create payments to receiving addresses the owner has approved.

mcp

payments

crypto

bitcoin

non-custodial

Installation steps

1Copy the config below
2Open ~/.codeium/windsurf/mcp_config.json
3Paste inside "mcpServers": {}
4Restart Windsurf

Configuration

File location: ~/.codeium/windsurf/mcp_config.json

mcp_config.jsonjson

{
  "send21": {
    "serverUrl": "https://send21.io/mcp",
    "headers": {
      "Authorization": "Bearer s21_YOUR_API_KEY"
    }
  }
}

Full server details GitHub Open Config Editor

Install in other clients

🤖Claude Desktop 💻Claude Code ⌨️Cursor ✨OpenAI ♊Gemini

For maintainers

If you maintain send21, add this badge to your README to show it's verified on CuratedMCP:

[![CuratedMCP Verified](https://www.curatedmcp.com/api/badge/send21)](https://www.curatedmcp.com/marketplace/send21)

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