send21 MCP Server
Agents create payment drafts with scoped keys that cannot spend. Humans sign in their own wallet. send21 never holds keys, never signs, never broadcasts.
send21 is a Business & Payments MCP (Model Context Protocol) server: Agents create payment drafts with scoped keys that cannot spend. Humans sign in their own wallet. send21 never holds keys, never signs, never broadcasts. It is MIT-licensed and self-hosted from its source repository. Listed on MCP Collection since September 2026.
About send21
Prepares non-custodial payment drafts and pay links for BTC, USDC, USDT, EURC on Bitcoin, Solana, Ethereum, Base. Never USDT or BTC on Base. Testnet demo at send21.io/demo.
How to connect send21 to Claude, Cursor or VS Code
send21 is self-hosted. Install it from the source repository, then register its start command in your MCP client's config (Claude Code, Cursor, Windsurf or VS Code).
{
"mcpServers": {
"send21": {
"command": "<start command from the README>",
"args": []
}
}
}The exact command (often npx, uvx or docker) is in the project README at send21.io/mcp.
send21 FAQ
What is send21?
send21 is a Model Context Protocol (MCP) server in the Business & Payments category. Agents create payment drafts with scoped keys that cannot spend. Humans sign in their own wallet. send21 never holds keys, never signs, never broadcasts. MCP servers expose tools that AI assistants like Claude can call during a conversation.
How do I use send21 with Claude or Cursor?
send21 is self-hosted. Install it from the source repository, then register its start command in your MCP client's config (Claude Code, Cursor, Windsurf or VS Code).
Is send21 free to use?
send21 is published under the MIT license, so the software itself is free to run. Hosted or API-backed servers may have their own usage tiers; check the project homepage.
Where is the source code for send21?
The source is at send21.io/mcp.