send21 MCP

Remote Model Context Protocol server for send21 — non-custodial payment drafts and pay links.

send21 prepares payment instructions for BTC, USDC, USDT, and EURC. The payer signs in their own wallet. send21 never holds keys, never signs, and never broadcasts.

Live endpoint (Streamable HTTP): https://send21.io/mcp
Descriptor: https://send21.io/.well-known/mcp.json
Agent docs: https://send21.io/llms.txt
OpenAPI: https://send21.io/swagger/v1/swagger.json
Site: https://send21.io

Connect

Point an MCP client at the remote server:

{
  "mcpServers": {
    "send21": {
      "url": "https://send21.io/mcp",
      "transport": "streamable-http",
      "headers": {
        "Authorization": "Bearer s21_YOUR_API_KEY"
      }
    }
  }
}

• Create scoped API keys at https://send21.io/api-keys (s21_…).
• Scopes such as drafts:write, drafts:read, webhooks:manage cannot move funds.
• tools/list works without authentication.

What the tools do

Typical tools (see live tools/list): create drafts / payment requests, fetch transaction templates, rates, and fee schedule. Signing and broadcast stay in the user’s wallet.

Brand

send21 — Direct. Non-custodial. Yours.
Contact: integration@send21.io

License

MIT