send21

Non-custodial payment drafts/pay links for BTC, USDC, USDT, EURC.

CommunityOnlineNo sign-inGlobalFreeCan modify data

What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Non-custodial payment drafts/pay links for BTC, USDC, USDT, EURC. Never holds keys.

    How to connect

    How to connect send21 to Claude

    The server address to paste into Claude settings:

    https://send21.io/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect send21 to ChatGPT

    The server address to paste into ChatGPT settings:

    https://send21.io/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect send21 to Cursor

    The server address to paste into Cursor settings:

    https://send21.io/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (9)

    Raw names from tools/list. Only developers need these.

    get_transaction_templateGet the multi-output transaction template for a draft: Bitcoin Core walletcreatefundedpsbt arguments and Electrum/Sparrow pay-to-many CSV. The operator's wallet funds, reviews, and signs it — send21 contains no signing code. Requires scope drafts:read.
    get_fee_scheduleGet the public send21 fee schedule: tiered percent by payment size in USD, min/max fee, and dust limit. No authentication needed.
    create_payment_requestCreate a payment request / checkout pay link (you are the RECEIVER asking to get paid). Price in any of 165 fiat currencies; the payer opens the returned payPath, picks one of the offered currencies (rate locks then), and pays a single QR-scannable transfer straight to your address. Requires scope drafts:write.
    list_address_bookList the account's saved addresses (label, address, network, direction: Sending = recipients the owner pays, Receiving = the owner's own addresses). Requires scope addressbook:read.
    get_draftGet a payment draft by id, including amounts, fee, quote, and status. Requires scope drafts:read.
    get_payment_requestGet a payment request by id: status (Open/Completed/Cancelled/Expired), pay path, offered currencies, and the underlying draft once the payer committed. Requires scope drafts:read.
    get_rateGet the current exchange rate for an asset in a fiat currency (rate = fiat units per 1 whole asset unit, with source provenance). Assets: Btc, Usdc, Usdt, Eurc. 165 ISO-4217 fiat currencies are supported.
    create_draftCreate a non-custodial payment draft (you are the SENDER paying a receiver address). Amount is either exact base units (sats for BTC, micro-units for stablecoins) via amountBaseUnits, or fiat-pegged via fiatCurrency+fiatAmount with the exchange rate locked at creation. Returns the draft incl. id, amounts, fee, and status. Funds move only when the sender signs in their own wallet — send21 never holds keys. Requires scope drafts:write.
    get_draft_statusLightweight status snapshot of a draft: status (AwaitingPayment/Seen/Confirmed/Expired/Cancelled), paying txid, confirmations. Cheap to poll. Requires scope drafts:read.