Pay x402 APIs in USDG on Robinhood Chain, borrow and repay a Priors credit line, check records.
Nothing to run from here
send21 is installed from its publisher's own source and answers where it runs, so this marketplace is not in the path of a single call. There is no address here to send one to, and a panel that pretended otherwise would be showing you an answer we made up. Install it and call it from your own client — the Installation tab has the entry for each one.
93/100
tool-list score
14
tools declared
remote
at its publisher
—
calls last 7d
What it does
Crypto pay links and API for people and AI agents. Non-custodial: send21 creates payment drafts and pay links; a person signs in their own wallet. 14 MCP tools. Sign in with OAuth at https://send21.io/mcp/oauth, or use an API key.
Quickstart
# 1 — add it to Claude Code
claude mcp add --scope user --transport http send21-mcp https://send21.io/mcp
# 2 — ask your agent for something these tools do
# get_transaction_template, get_fee_schedule, create_payment_request and 11 more
send21 costs nothing on mcprush: there is no plan to choose here, no cap to set and nothing mcprush can bill you for.
Publisher
Installation
Where are you running it?
Every route below installs the same thing and ends at the same approval screen. Nothing here runs on your machine and nothing runs on ours: this server answers at its publisher’s own address, and what you install is the connection straight to it.
Claude Codedeclared by this listing
This is a public server: it answers at its publisher’s own address and this marketplace is not in the path. Claude Code registers it in one command; --scope user makes it available in every project. The transport below is http, as the publisher's own manifest declares it.
claude mcp add --scope user --transport http send21-mcp https://send21.io/mcpReconnect, or start a new session, and the tools appear in the model’s tool list.
Free on mcprush, and it answers at its publisher’s own address: this marketplace is not in the path, so there is no key of ours to hold and no card to add — some of its tools take a key of its publisher’s own, and the rest work without.
What it asks of you
Nothing is required, but it can take Authorization header (Bearer s21_<api key>, created by the account owner at https://send21.io/api-keys) if you want to set it. Its publisher says some of its tools need it, and the rest work without.
What it writes
One config entry pointing straight at the publisher’s own address — this marketplace is not in the path, and nothing from this listing executes on your machine.
What you approve
14 tools, with what each one reads, writes and reaches shown before you agree — the same list on every route above. Read the tool surface.
Tool surface
What the model actually sees. Descriptions are diffed on every release — see version history.
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.
| Parameter | Type | Required | Notes |
|---|---|---|---|
| draftId | string | yes | Draft id (GUID) |
Get the public send21 fee schedule: tiered percent by payment size in USD, min/max fee, and dust limit. No authentication needed.
No parameter schema on file.
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. On accounts with the policy ApprovedOnly (see get_account_status) every address must be one of the owner's approved
| Parameter | Type | Required | Notes |
|---|---|---|---|
| fiatCurrency | string | yes | Fiat currency the request is priced in, e.g. USD, EUR, SEK |
| fiatAmount | number | yes | Amount in the fiat currency |
| options | array | yes | Currencies the payer may choose from, each with your receiving address |
| orderId | string/null | no | Your own order/reference id, echoed in webhooks for reconciliation |
| memo | string/null | no | Message shown to the payer (max 500 chars) |
| expiryHours | integer/null | no | Hours until the request expires (default 24) |
| idempotencyKey | string/null | no | Idempotency key. A retry with the same key and the same parameters returns the original request; the same key with another amount, currency or address is refused (422) and creates nothing |
| declineNote | string/null | no | What happens if the payer does not pay (plain text, max 200 chars). Shown on the pay page under the amount as "If you don't pay:". Use it when handing an over-budget purchase to a human, e.g. "The ord |
| shortfallAbsorbUpToPercent | number/null | no | Accept short payments automatically when they are at most this percent below the price (0 to 10); the receiver absorbs the difference. Overpayments always wait for a human. Omit to have every differin |
| reuseOpenForOrder | boolean/null | no | True: if an open, unexpired request with the same orderId exists, return it instead of creating a second pay link for the same order (only when it asks for the same amount, currency and addresses). Re |
Propose an address for the owner to approve: one of the owner's own receiving addresses (for pay links) or the address of someone the owner pays (for drafts). It is saved unapproved and the owner gets an email. On accounts with the policy ApprovedOnly, API keys can only use approved addresses, and only the owner can approve one, signed in to the send21 app with a passkey or authenticator code. No
| Parameter | Type | Required | Notes |
|---|---|---|---|
| label | string | yes | A label the owner will recognise, e.g. "My Phantom wallet" (unique per account) |
| address | string | yes | The address, or for BTC over Lightning the Lightning address (name@wallet.com) |
| network | string | yes | Network the address lives on: Mainnet (Bitcoin, also for Lightning addresses), Solana, Ethereum, Base, Arbitrum or Polygon |
| direction | string/null | no | Receiving (default): the owner's own address, for pay links. Sending: someone the owner pays, for drafts. |
What stands between you and a live pay link: whether the owner's email is confirmed, the receiving-address policy, how many addresses are approved or waiting for approval, unsettled fees, your key's scopes, and the next steps. Requires scope drafts:read.
No parameter schema on file.
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.
No parameter schema on file.
Get a payment draft by id, including amounts, fee, quote, and status. Requires scope drafts:read.
| Parameter | Type | Required | Notes |
|---|---|---|---|
| draftId | string | yes | Draft id (GUID) |
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
| Parameter | Type | Required | Notes |
|---|---|---|---|
| draftId | string | yes | Draft id (GUID) |
| preimage | string | yes | Payment preimage, 64 hex characters |
Create a send21 account for your human owner, without a key. The owner gets an email with a link to take the account over; until they do, nothing can be created. Returns a bootstrap API key ONCE (save it and send it as Authorization: Bearer on every later call; reconnect this MCP client with it). The key can read, propose addresses and check get_account_status; it can create pay links only after t
| Parameter | Type | Required | Notes |
|---|---|---|---|
| ownerEmail | string | yes | The human owner's email address (not yours); they receive the link to take the account over |
| agentName | string/null | no | Your name as the owner will see it: letters, digits, spaces and . _ - ( ), at most 50 |
| intendedUse | string/null | no | What you will use the account for, shown to the owner (max 300 characters) |
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.
| Parameter | Type | Required | Notes |
|---|---|---|---|
| paymentRequestId | string | yes | Payment request id (GUID) |
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.
| Parameter | Type | Required | Notes |
|---|---|---|---|
| fiatCurrency | string | yes | Fiat currency code, e.g. USD, EUR, SEK |
| asset | string | yes | Asset: Btc, Usdc, Usdt, Eurc, Sol, or Eth |
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 the
| Parameter | Type | Required | Notes |
|---|---|---|---|
| receiverAddress | string | yes | Receiver address (Bitcoin bc1..., Solana base58, or 0x... for Ethereum, Base, Arbitrum and Polygon) |
| network | string | yes | Network: Mainnet, Solana, Ethereum, Base, Arbitrum, Polygon (test: Testnet4, Signet, Regtest, SolanaDevnet, EthereumSepolia, BaseSepolia, ArbitrumSepolia, PolygonAmoy) |
| currency | string/null | no | Asset: Btc (default), Usdc, Usdt, Eurc, Sol (native SOL on Solana), or Eth (native ETH on Ethereum, Base, Arbitrum) |
| amountBaseUnits | integer/null | no | Exact amount in base units (sats / micro-units / lamports / gwei); omit when using fiat pricing |
| fiatCurrency | string/null | no | Fiat currency code for fiat-pegged amount, e.g. USD |
| fiatAmount | number/null | no | Fiat amount; requires fiatCurrency |
| memo | string/null | no | Free-text memo shown on the draft (max 500 chars) |
| idempotencyKey | string/null | no | Idempotency key. A retry with the same key and the same parameters returns the original draft; the same key with another receiver, amount, currency or network is refused (422) and creates nothing |
| shortfallAbsorbUpToPercent | number/null | no | Accept short payments automatically when they are at most this percent below the amount (0 to 10); the receiver absorbs the difference. Overpayments always wait for a human. |
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.
| Parameter | Type | Required | Notes |
|---|---|---|---|
| draftId | string | yes | Draft id (GUID) |
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:rea
| Parameter | Type | Required | Notes |
|---|---|---|---|
| draftId | string | yes | Draft id (GUID) |
Free
$0 forever
- Every tool — any call limit is its publisher’s, not ours
- No card, and mcprush charges nothing for it
- Runs at its publisher’s own address — this marketplace is not in the path
- Nothing to cap, because mcprush bills nothing
What counts against your monthly calls
| Tool | Unit | Calls used | Out of the allowance |
|---|
Nothing here is billable: mcprush charges nothing to install send21 or to call it, at any volume.
Call allowance · this installenforced at the gateway
Monthly allowance, in calls
—
—
Alert at 80% · then the tool returns a normal MCP error
Used this month: —
ATool-list grade · score 93 / 100
Release 1.7.0 · scanned 22 Oct 2026
Graded from the tools this server lists, not from its source code.
Two independent axes, because powerful and malicious are different questions. The grade is threat only. The capability level is blast radius, and it is never a penalty on the grade — it is priced as one subtract-only term in the score, where you can see it.
Threat score100
Client score93
Findings0 threat · 0 capability
Capabilitymoderate
Coveragemanifest
Verificationnot in this report
Surface digest652abe8caf9d124160890e1326ffe4f7df54b12ecd1606c9b4ddfef9f5be43ae
Score vectorthreat 100 → client 93
| Term | Level | What it prices | Points |
|---|---|---|---|
| capability-exposure | moderate | capability blast radius (moderate) — client exposure if the model is manipulated | −3 |
| coverage-honesty | manifest | inspection depth (manifest) — how much of the target the scan could see | −4 |
score = clamp(round(threatScore − E_cap − E_ver − E_cov), 0, 100). No model, no opinion, no network call at scoring time: the same methodology version against the same bytes always produces this number, and every line above is a field of the report rather than a summary of it.
What the scan could actually read
A grade is only as meaningful as its coverage, so the scanner publishes its own depth before it publishes its result.
The scan read each tool’s name, description, input schema and annotations exactly as the server listed them the last time it answered us; no code was reviewed. We ask the server again about once a month, and a list that changed is graded again.
Tool surfaceread
Implementation sourcenot available
Package metadatanot available
Live transportnot available
The implementation source was not read — this reflects the declared tool metadata only.
Capability — what it could do if the model were manipulated
Tags derived from each tool’s schema and the implementation, not from what the tool calls itself. moderate is the level these add up to.
| Tool | Capability tags | Why the tag was assigned |
|---|---|---|
| get_transaction_template | no tags | |
| get_fee_schedule | no tags | |
| create_payment_request | state-write | state-write: declares readOnlyHint: false |
| propose_receiving_address | state-write | state-write: declares readOnlyHint: false |
| get_account_status | no tags | |
| list_address_book | no tags | |
| get_draft | no tags | |
| submit_lightning_proof | state-write | state-write: declares readOnlyHint: false |
| create_account | external-sink | external-sink: declares readOnlyHint: false, openWorldHint: true |
| get_payment_request | no tags | |
| get_rate | no tags | |
| create_draft | state-write | state-write: declares readOnlyHint: false |
| list_draft_quotes | no tags | |
| get_draft_status | no tags |
Toxic-flow graph
The lethal trifecta, checked as a graph rather than as a checklist: untrusted input, a sensitive source and an external sink have to meet before there is a path worth worrying about.
The public result for this release does not print the flow graph, so there is nothing to show here. That is not the same as "no paths were found": what the scan did read is above, under coverage.
Supply chain and provenance
Integrityfirst-seen
Surface digest652abe8caf9d1241
Scanned2026-10-22
This is the first scan of this surface here, so there is nothing yet to compare it against.
Every result on this tab comes from one deterministic pass over the published package — offline, rule by rule, and auditable line by line above. Same methodology version, same bytes, same score.
Release history
This is an address its publisher runs: which release it serves is theirs to choose, so there is nothing here to pin. The history below is for reading; the current release on file is 1.7.0.
1.7.0
22 Oct 2026
latest- 14 tools with titles and annotations; OAuth sign-in at https://send21.io/mcp/oauth (API key still supported).
1.5.0
20 Oct 2026
No release note was published with this version.
1.3.1
undated
- The version this listing was on when mcprush began following its releases. The registry was not asked when it shipped, so this row carries no date.
—
no reviews yet
Who can review
One review per account, from a signed-in account that does not publish this listing. Nothing else is asked — you can say what you think before you install it. Publishers can reply once per review, and a review can be edited or deleted by whoever wrote it.
Sign in to write one
Any signed-in account that does not publish send21 can review it, once — before installing it or after. A review from an account that has installed it is marked as one.
No reviews yet
Nobody has reviewed this listing. The rating on the card is the mean of the reviews written here and nothing else, so there is no rating until somebody writes the first — which takes a signed-in account that does not publish it, and nothing else.