send21

Non-custodial payment drafts and pay links for BTC, USDC, USDT, and EURC. Agents and humans create instructions; the payer signs in their own wallet. Never holds keys or funds.

URL

https://send21.io

Category

api

Pricing

freemium

Tags

payments bitcoin mcp non-custodial agents

Machine endpoints

llms_txt: https://send21.io/llms.txt
openapi: https://send21.io/swagger/v1/swagger.json
mcp: https://send21.io/mcp

Submitted by

send21io

Listed

2026-09-04 · tier: free

Machine-readable: listing JSON · full registry · llms.txt

Badges

Paste either into your README. Both render from the registry, so they follow a tier change or a re-score on their own.

[![AI Agent Ready](https://index.percall.dev/badge.svg?slug=send21)](https://index.percall.dev/l/send21.html)
[![Agent Readability](https://index.percall.dev/badge.svg?slug=send21&show=score)](https://index.percall.dev/l/send21.html)

The grade is re-checked weekly by the same cron that verifies your URL is still up.