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8 clients · secrets stay placeholders

JSON (mcpServers)Claude CodeCodexOpenCodeCursorVS CodeGemini CLIGoose

{
  "mcpServers": {
    "send21io": {
      "type": "http",
      "url": "https://send21.io/mcp",
      "headers": {
        "Authorization": "Bearer ${SEND21IO_TOKEN}"
      }
    }
  }
}

claude mcp add --transport http send21io https://send21.io/mcp --header "Authorization: Bearer ${SEND21IO_TOKEN}"

[mcp_servers.send21io]
url = "https://send21.io/mcp"
bearer_token_env_var = "SEND21IO_TOKEN"

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "send21io": {
      "type": "remote",
      "url": "https://send21.io/mcp",
      "enabled": true,
      "headers": {
        "Authorization": "Bearer {env:SEND21IO_TOKEN}"
      }
    }
  }
}

{
  "mcpServers": {
    "send21io": {
      "type": "http",
      "url": "https://send21.io/mcp",
      "headers": {
        "Authorization": "Bearer ${SEND21IO_TOKEN}"
      }
    }
  },
  "deeplink": "cursor://anysphere.cursor-deeplink/mcp/install?name=send21io&config=eyJ0eXBlIjoiaHR0cCIsInVybCI6Imh0dHBzOi8vc2VuZDIxLmlvL21jcCIsImhlYWRlcnMiOnsiQXV0aG9yaXphdGlvbiI6IkJlYXJlciAke1NFTkQyMUlPX1RPS0VOfSJ9fQ%3D%3D"
}

{
  "servers": {
    "send21io": {
      "type": "http",
      "url": "https://send21.io/mcp",
      "headers": {
        "Authorization": "Bearer ${SEND21IO_TOKEN}"
      }
    }
  }
}

{
  "mcpServers": {
    "send21io": {
      "httpUrl": "https://send21.io/mcp",
      "headers": {
        "Authorization": "Bearer ${SEND21IO_TOKEN}"
      }
    }
  }
}

extensions:
  "send21io":
    enabled: true
    name: "send21io"
    type: streamable_http
    uri: "https://send21.io/mcp"
    headers:
      "Authorization": "Bearer ${SEND21IO_TOKEN}"
    timeout: 300

Placeholders to fill from your own secret store: ${SEND21IO_TOKEN}. The registry never accepts secret values.

Quality 67 / 100needs work

protocol88 · weight 25

pass
protocol.modernsupports 2026-07-28 (server/discover)
pass
protocol.statelessanswers without a session
pass
protocol.transportstreamable HTTP
warn
protocol.list_ttltools/list declares ttlMs 0, so clients re-fetch it on every use

authorizationn/a · weight 15

n/a
auth.prm, auth.as_metadata, auth.cimdno remote uses OAuth
n/a
auth.secret_in_urlno templated URL

tool hygiene71 · weight 30

pass
tools.descriptionsevery tool has a description
pass
tools.description_lengthdescriptions are concise
pass
tools.schemasevery tool has an object input schema
fail
tools.annotationsno tool declares readOnlyHint or destructiveHint, so clients cannot tell safe calls from risky ones
fail
tools.directory_hintsno tool declares all four of readOnlyHint, destructiveHint, idempotentHint and openWorldHint; missing: list_address_book (readOnlyHint, destructiveHint, idempotentHint, openWorldHint); get_draft (readOnlyHint, destructiveHint, idempotentHint, openWorldHint); get_rate (readOnlyHint, destructiveHint, idempotentHint, openWorldHint); …
pass
tools.token_costabout 2,220 tokens to load every tool
pass
tools.api_dumptools are not a one-to-one API dump

stability25 · weight 15

warn
stability.changes19 tool changes in 30 days
fail
stability.rug_pull1 tools kept their name but changed most of their description in 30 days; review before trusting them

dependenciesn/a · weight 15

n/a
deps.known_vulns, deps.mcp_sdk_version, deps.resolvableno npm or PyPI package

11 tools, about 2,220 tokens to load them all · tool set dab5957c75e0 · tools last changed 2026-10-13 · checked 2026-10-19 10:20 UTC

Tool changes

2026-10-13create_draftchangedinput schema
2026-10-13create_payment_requestchangedinput schema
2026-10-12get_draft_statuschangeddescriptionmeaning changed
before
Lightweight status snapshot of a draft: status (AwaitingPayment/Seen/Confirmed/Expired/Cancelled), paying txid, confirmations. Cheap to poll. Requires scope drafts:read.
after · 48% of words in common
Lightweight status snapshot of a draft: status (AwaitingPayment/Seen/Confirmed/Expired/Cancelled), paying txid, confirmations, and reviewState when a transfer with a different amount arrived (pending = needs the receiver's decision and the draft is not paid; accepted; rejected; unresolved = the draft expired while undecided, the money is with the receiver). Cheap to poll. Requires scope drafts:read.
2026-10-12create_payment_requestchangedinput schema
2026-10-12list_draft_quotesadded
List every quote (rate lock) of a fiat-priced draft, oldest first. Quotes never change; a re-quote adds a new one with its own id. Each has a sha256 (RFC 8785 JCS + SHA-256). Requires scope drafts:read.
2026-10-12create_draftchangedinput schema
2026-10-12get_payment_requestchangeddescription
before
Get 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.
after · 52% of words in common
Get a payment request by id: status (Open/Completed/Cancelled/Expired), pay path, offered currencies, and the underlying draft once the payer committed. Includes changeSignals and changeNotes: what is unusual compared with the account's paid payments (new_address, new_asset, unusual_amount), the same lines the payer sees on the pay page; empty when nothing is unusual. Requires scope drafts:read.
2026-10-12create_payment_requestchangedinput schema
2026-10-07get_ratechangeddescription
before
Get 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, Sol, Eth. 165 ISO-4217 fiat currencies are supported. Requires an API key.
after · 95% of words in common
Get 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, Sol, Eth. 161 ISO 4217 fiat currencies are supported. Requires an API key.
2026-10-07submit_lightning_proofadded
Confirm a paid Lightning draft with its proof of payment: the 64-character preimage the paying wallet shows after a Lightning payment. Needed for drafts with a pasted bolt11 invoice, and for Lightning addresses whose provider does not report payments. send21 checks that SHA-256 of the preimage equals the invoice's payment hash; the draft then confirms within about 30 seconds. Requires scope drafts:write.

Showing the latest 10. Full history: list_changes · trend: quality JSON.

Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed. How it is computed.

Trust 79 / 100

no-repository

provenance45

liveness99

freshness100

hygiene80

+website +reachable +uptime-96% +updated-0d-ago -no-repository

Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed. How it is computed.

Endpoints

remote	auth	reachable	uptime 30d	p50	protocol	last ok
`https://send21.io/mcp` streamable-http	none	yes	96%	289 ms	2026-07-28	2026-10-19

Tools (11)

`create_draft`	Create 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, lamports for SOL, gwei for ETH) 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.
`create_payment_request`	Create a payment request / checkout pay link (you are the RECEIVER asking to get paid). Price in any of 161 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.
`get_draft`	Get a payment draft by id, including amounts, fee, quote, and status. Requires scope drafts:read.
`get_draft_status`	Lightweight status snapshot of a draft: status (AwaitingPayment/Seen/Confirmed/Expired/Cancelled), paying txid, confirmations, and reviewState when a transfer with a different amount arrived (pending = needs the receiver's decision and the draft is not paid; accepted; rejected; unresolved = the draft expired while undecided, the money is with the receiver). Cheap to poll. Requires scope drafts:read.
`get_fee_schedule`	Get the public send21 fee schedule: tiered percent by payment size in USD, min/max fee, and dust limit. No authentication needed.
`get_payment_request`	Get a payment request by id: status (Open/Completed/Cancelled/Expired), pay path, offered currencies, and the underlying draft once the payer committed. Includes changeSignals and changeNotes: what is unusual compared with the account's paid payments (new_address, new_asset, unusual_amount), the same lines the payer sees on the pay page; empty when nothing is unusual. Requires scope drafts:read.
`get_rate`	Get 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, Sol, Eth. 161 ISO 4217 fiat currencies are supported. Requires an API key.
`get_transaction_template`	Get the transaction template for an on-chain draft: every output to pay, plus walletcreatefundedpsbt arguments and a pay-to-many CSV on Bitcoin, or payment URIs (and calldata on EVM chains) on Solana, Ethereum, Base, Arbitrum and Polygon. The sender's own wallet funds, reviews and signs it; send21 contains no signing code. Not for Lightning drafts (pay their invoice). Requires scope drafts:read.
`list_address_book`	List the account's saved addresses (label, address, network, direction: Sending = recipients the owner pays, Receiving = the owner's own addresses). Requires scope addressbook:read.
`list_draft_quotes`	List every quote (rate lock) of a fiat-priced draft, oldest first. Quotes never change; a re-quote adds a new one with its own id. Each has a sha256 (RFC 8785 JCS + SHA-256). Requires scope drafts:read.
`submit_lightning_proof`	Confirm a paid Lightning draft with its proof of payment: the 64-character preimage the paying wallet shows after a Lightning payment. Needed for drafts with a pasted bolt11 invoice, and for Lightning addresses whose provider does not report payments. send21 checks that SHA-256 of the preimage equals the invoice's payment hash; the draft then confirms within about 30 seconds. Requires scope drafts:write.

Schemas: list_tools.

Similar MCP servers

Official server.json

{
  "name": "io.github.send21io/mcp",
  "icons": [
    {
      "src": "https://send21.io/branding/send21-icon-new.svg",
      "sizes": [
        "any"
      ],
      "mimeType": "image/svg+xml"
    },
    {
      "src": "https://send21.io/apple-touch-icon-new.png",
      "sizes": [
        "180x180"
      ],
      "mimeType": "image/png"
    }
  ],
  "title": "send21",
  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
  "remotes": [
    {
      "url": "https://send21.io/mcp",
      "type": "streamable-http",
      "headers": [
        {
          "name": "Authorization",
          "isSecret": true,
          "description": "Bearer s21_<api key>, created by the account owner at https://send21.io/api-keys"
        }
      ]
    }
  ],
  "version": "1.4.1",
  "websiteUrl": "https://send21.io/docs/mcp",
  "description": "Crypto pay links and API for people and AI agents. BTC, Lightning, USDC, USDT, EURC, SOL, ETH."
}