# send21-io

**Canonical:** https://apis.io/providers/send21-io/  
**Website:** https://send21.io/  
**APIs profiled:** 1

Send21 provides a non-custodial crypto payment link service and API for people and AI agents. Users can create pay links or invoices priced in various cryptocurrencies, including BTC, USDC, USDT, EURC, SOL, and ETH, and pay directly from their wallets via on-chain or Lightning. The platform emphasizes security, stating that it never holds users' money or private keys, and offers documentation, pricing, and demo pages for developers and businesses.

## Kin Score — 56.9 / 100 (strong)

Scored 2026-10-31 under rubric 0.25.0.

| Facet | Score |
|---|---|
| Discoverability | 66.1 |
| Contract Quality | 63.9 |
| Contract Governance | 70.9 |
| Operational Transparency | 23.7 |
| Developer Ergonomics | 45.2 |
| Access Clarity | 63.7 |

Regulatory layer — **Payments**: 25.8 (matched via tags).

## Agent readiness — 54.9 (agent-ready)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | unknown |
| Reversibility Documented | no |
| MCP Server | documented |
| Auth Clarity | served |
| Idempotency | documented |
| Error Semantics | verified |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | unknown |
| Agent Skills | no |
| Well Known Catalog | yes |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |
| Delegated Identity | served |
| Protected Resource Metadata | verified |
| Dynamic Client Registration | yes |
| Agentic Commerce | no |
| Pagination Ratio | no |
| Operation Distinctiveness | mostly |

## APIs (13)

- **send21-io Account API** — The Account API from send21-io — 2 operation(s) for account.
- **send21-io Auth API** — The Auth API from send21-io — 26 operation(s) for auth.
- **send21-io Checkout API** — The Checkout API from send21-io — 3 operation(s) for checkout.
- **send21-io Demo API** — The Demo API from send21-io — 3 operation(s) for demo.
- **send21-io Drafts API** — The Drafts API from send21-io — 13 operation(s) for drafts.
- **send21-io Fees API** — The Fees API from send21-io — 3 operation(s) for fees.
- **send21-io Rates API** — The Rates API from send21-io — 1 operation(s) for rates.
- **send21-io Recurring Templates API** — The RecurringTemplates API from send21-io — 4 operation(s) for recurringtemplates.
- **send21-io Suggestions API** — The Suggestions API from send21-io — 1 operation(s) for suggestions.
- **send21-io Webhooks API** — **send21 calls your server when a draft changes.** Register an endpoint with `POST /api/v1/webhooks` (scope `webhooks:manage`) and pick the events you want. The response contain...
- **send21-io Address Book API** — The Address Book API from send21-io — 2 operation(s) for address book.
- **send21-io API Keys API** — The API Keys API from send21-io — 2 operation(s) for api keys.
- **send21-io Payment Requests API** — The Payment Requests API from send21-io — 3 operation(s) for payment requests.

## Agentic access (1)

- **Send21 Io Agentic Access** — 146 operations · 102 acting · 4 human-in-the-loop

## Security (3)

- **Send21 Io Authentication** — 1 scheme
- **Send21 Io Domain Security** — TLSv1.3 · HSTS · DMARC
- **Send21 Io Vulnerability Disclosure** — security.txt · contact published

## Plans (1)

- **Send21 Io Plans Pricing**

## Tags

Company, Payments, Crypto, API, Non-custodial, AI

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/send21-io/). Scores are computed from the provider's own public artifacts under a published rubric.