# send21 (remote · send21.io)

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

- Trust score: 74/100 (medium)
- Change this week: +3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-20

## Components

- remote · `send21.io`: 74/100 (this document), [markdown](https://verifymcp.io/servers/send21io-mcp/send21.md), [page](https://verifymcp.io/servers/send21io-mcp/send21)

## Channel facts

- Endpoint: `https://send21.io/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-09-20.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 9 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 80/100
  - AI-judged instruction clarity (excellent).
  - Tool/resource definitions use about 957 tokens (~106/item across 9 items; 9 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 47/100
  - Stability observed for 14 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 9 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 9 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the send21 MCP server?

send21 is a hosted endpoint at https://send21.io/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http send21io-mcp 'https://send21.io/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "send21io-mcp": {
      "url": "https://send21.io/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "send21io-mcp": {
      "type": "http",
      "url": "https://send21.io/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.send21io-mcp]
url = "https://send21.io/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "send21io-mcp": {
      "type": "remote",
      "url": "https://send21.io/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add send21io-mcp --url 'https://send21.io/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  send21io-mcp:
    url: "https://send21.io/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "send21io-mcp": {
      "Transport": "http",
      "Url": "https://send21.io/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add send21io-mcp -t streamable-http -u 'https://send21.io/mcp'
```

### Other

```json
{
  "mcpServers": {
    "send21io-mcp": {
      "type": "http",
      "url": "https://send21.io/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-09-19 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 40 to 43. That category is still filling its 30-day observation window: 12 days of observed history at the previous scan, 13 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-17 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 33 to 37. That category is still filling its 30-day observation window: 10 days of observed history at the previous scan, 11 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-15 (score 72, +1)

No change was recorded against any check on this day. Stability & Change Management went from 27 to 30. That category is still filling its 30-day observation window: 8 days of observed history at the previous scan, 9 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-13 (score 71, +1)

No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-11 (score 70, +1)

No change was recorded against any check on this day. Stability & Change Management went from 13 to 17. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 5 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-08 (score 69, +1)

No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-07 (score 68, 0)

- [functional improvement] Stability: unverified → 0.03

### 2026-09-06 (score 68)

First indexed and scored.

## MCP tools (9)

### `get_transaction_template` (~76 tokens)

Get 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.

Input parameters:

- `draftId` (string, required): Draft id (GUID)

### `get_fee_schedule` (~38 tokens)

Get the public send21 fee schedule: tiered percent by payment size in USD, min/max fee, and dust limit. No authentication needed.

### `create_payment_request` (~215 tokens)

Create 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.

Input parameters:

- `expiryHours` (integer|null, required): Hours until the request expires (default 24)
- `fiatAmount` (number, required): Amount in the fiat currency
- `fiatCurrency` (string, required): Fiat currency the request is priced in, e.g. USD, EUR, SEK
- `idempotencyKey` (string|null, required): Idempotency key — retries with the same key return the original request
- `memo` (string|null, required): Message shown to the payer (max 500 chars)
- `options` (array, required): Currencies the payer may choose from, each with your receiving address
- `orderId` (string|null, required): Your own order/reference id — echoed in webhooks for reconciliation

### `list_address_book` (~45 tokens)

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.

### `get_draft` (~44 tokens)

Get a payment draft by id, including amounts, fee, quote, and status. Requires scope drafts:read.

Input parameters:

- `draftId` (string, required): Draft id (GUID)

### `get_payment_request` (~61 tokens)

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.

Input parameters:

- `paymentRequestId` (string, required): Payment request id (GUID)

### `get_rate` (~102 tokens)

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. 165 ISO-4217 fiat currencies are supported.

Input parameters:

- `asset` (string, required): Asset: Btc, Usdc, Usdt, or Eurc
- `fiatCurrency` (string, required): Fiat currency code, e.g. USD, EUR, SEK

### `create_draft` (~317 tokens)

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) 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.

Input parameters:

- `amountBaseUnits` (integer|null, required): Exact amount in base units (sats / micro-units); omit when using fiat pricing
- `currency` (string|null, required): Asset: Btc (default), Usdc, Usdt, or Eurc
- `fiatAmount` (number|null, required): Fiat amount; requires fiatCurrency
- `fiatCurrency` (string|null, required): Fiat currency code for fiat-pegged amount, e.g. USD
- `idempotencyKey` (string|null, required): Idempotency key — retries with the same key return the original draft
- `memo` (string|null, required): Free-text memo shown on the draft (max 500 chars)
- `network` (string, required): Network: Mainnet, Solana, Ethereum, Base (test: Testnet4, Signet, Regtest, SolanaDevnet, EthereumSepolia, BaseSepolia)
- `receiverAddress` (string, required): Receiver address (Bitcoin bc1…, Solana base58, or 0x… for Ethereum/Base)

### `get_draft_status` (~59 tokens)

Lightweight status snapshot of a draft: status (AwaitingPayment/Seen/Confirmed/Expired/Cancelled), paying txid, confirmations. Cheap to poll. Requires scope drafts:read.

Input parameters:

- `draftId` (string, required): Draft id (GUID)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/send21io-mcp/send21#diagnostics

## Score history

- 2026-09-20: 74
- 2026-09-19: 74
- 2026-09-18: 73
- 2026-09-17: 73
- 2026-09-16: 72
- 2026-09-15: 72
- 2026-09-14: 71
- 2026-09-13: 71
- 2026-09-12: 70
- 2026-09-11: 70
- 2026-09-10: 69
- 2026-09-09: 69
- 2026-09-08: 69
- 2026-09-07: 68
- 2026-09-06: 68

## Common questions

### What is the send21 MCP server?

send21 is an MCP server listed in the public MCP registry as io.github.send21io/mcp. Non-custodial payment drafts/pay links for BTC, USDC, USDT, EURC. Never holds keys. This page covers its hosted endpoint (https://send21.io/mcp).

### Is the send21 MCP server safe to use?

send21 scores 74 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the send21 MCP server expose?

send21 exposes 9 tools: get_transaction_template, get_fee_schedule, create_payment_request, list_address_book, get_draft, and 4 more. Their descriptions and schemas cost roughly 957 tokens of context every time the server is loaded.

### Does the send21 MCP server require authentication?

No. We connected to send21 without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the send21 MCP server still maintained?

send21 is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://send21.io/mcp
- Repository: https://github.com/send21io/mcp
- Website: https://send21.io/
- Changelog RSS feed: https://verifymcp.io/servers/send21io-mcp/send21.xml
- Changelog JSON feed: https://verifymcp.io/servers/send21io-mcp/send21.json
- HTML version of this page: https://verifymcp.io/servers/send21io-mcp/send21