Developer docs

curl -X POST https://api.stablc.xyz/v1/payment-links \
  -H "Content-Type: application/json" \
  -d '{
    "amount":        "50",
    "expiresAt":     "2026-06-01T00:00:00Z",
    "note":          "Invoice #42",
    "webhookUrl":    "https://yourapp.com/webhook",
    "webhookSecret": "your-signing-secret",
    "options": [
      { "chain": "ethereum-sepolia", "token": "USDC", "toAddress": "0xYourWalletAddress" }
    ]
  }'

// Node.js — no SDK or API key needed, plain fetch works
const res = await fetch('https://api.stablc.xyz/v1/payment-links', {
  method:  'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    amount:    '50',                      // 50 USDC, human-readable
    expiresAt: '2026-06-01T00:00:00Z',    // link stops working after this
    note:      'Invoice #42',
    options: [
      { chain: 'ethereum-sepolia', token: 'USDC', toAddress: '0xYourWalletAddress' }
    ],
  }),
})

const { url, secret } = await res.json()
// url    → send this to your customer
// secret → store it now; it is shown only once

{
  "url":    "https://checkout.stablc.xyz/p/018e6b7f-...#sig=a3f9bc2d...",
  "secret": "clh_sec_4a7f2e..."
}

// The checkout URL from POST /v1/payment-links looks like:
// https://checkout.stablc.xyz/p/<id>#sig=<hex>
// Insert ?popup=1 before the fragment to enable full-window popup mode.

function openCheckoutPopup(checkoutUrl) {
  const url = checkoutUrl.replace(/#/, '?popup=1#')
  return window.open(url, 'stablc-checkout', 'width=420,height=680,resizable=no')
}

const popup = openCheckoutPopup(link.url)

// Popup mode does not emit postMessage events — poll your backend for status
const poll = setInterval(async () => {
  const data = await fetch(`/api/payment-links/${linkId}`).then(r => r.json())
  if (data.status === 'PAID') {
    clearInterval(poll)
    popup?.close()
    onPaymentConfirmed(data)
  }
}, 3000)

<!-- Embed the checkout in your page -->
<iframe
  src="https://checkout.stablc.xyz/p/<id>#sig=<hex>"
  allow="ethereum"
  width="400"
  height="620"
  style="border:none; border-radius:12px;"
></iframe>

<script>
window.addEventListener('message', (event) => {
  if (event.origin !== 'https://checkout.stablc.xyz') return
  const { type, detail } = event.data

  if (type === 'stablc:paid') {
    // detail: { txHash?: string, amount: string, token: string }
    fulfillOrder(detail)
  }
  if (type === 'stablc:close') {
    // payer closed the checkout panel
    hideIframe()
  }
  if (type === 'stablc:error') {
    console.error('Checkout error:', detail.message)
  }
})
</script>

// Claude Desktop — claude_desktop_config.json
{
  "mcpServers": {
    "stablc": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://api.stablc.xyz/mcp"]
    }
  }
}

# MCP uses streamable HTTP — the client sends JSON-RPC over POST /mcp
# Most users connect via an MCP client (Claude Desktop, Cursor, etc.)
# Direct HTTP example (initialize):
curl -X POST https://api.stablc.xyz/mcp \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"my-agent","version":"1.0"}}}'

{
  "name": "create_payment_link",
  "description": "Create a stablc payment link. Returns a checkout URL to send to the payer and a secret for managing the link.",
  "input_schema": {
    "type": "object",
    "required": ["amount", "expiresAt", "options"],
    "properties": {
      "amount": {
        "type":        "string",
        "description": "Human-readable decimal amount (e.g. '10' for 10 USDC or '10.50' for 10.50 USDC). Do not pass raw base units — the API calculates those internally."
      },
      "note": {
        "type":        "string",
        "description": "Human-readable label shown on the checkout page (e.g. 'Invoice #42')."
      },
      "expiresAt": {
        "type":        "string",
        "description": "ISO-8601 expiry datetime (UTC). Must be in the future."
      },
      "webhookUrl": {
        "type":        "string",
        "description": "HTTPS URL to POST payment.confirmed events to."
      },
      "options": {
        "type":        "array",
        "description": "One entry per accepted (chain, token, wallet) combination.",
        "items": {
          "type":     "object",
          "required": ["chain", "token", "toAddress"],
          "properties": {
            "chain":     { "type": "string", "description": "Chain slug, e.g. 'ethereum-sepolia'. Call get_supported_chains first to get valid slugs." },
            "token":     { "type": "string", "description": "Token symbol, e.g. 'USDC'." },
            "toAddress": { "type": "string", "description": "Ethereum wallet address to receive funds." }
          }
        }
      }
    }
  }
}

{
  "name": "get_payment_link",
  "description": "Fetch the current state of a payment link. Use this to check whether a payment has been received (status = PAID).",
  "input_schema": {
    "type": "object",
    "required": ["id", "secret"],
    "properties": {
      "id":     { "type": "string", "description": "Payment link UUID returned by create_payment_link." },
      "secret": { "type": "string", "description": "clh_sec_ bearer token returned by create_payment_link." }
    }
  }
}

{
  "name": "get_supported_chains",
  "description": "Returns all chains and tokens supported by stablc. Call this before creating a payment link if you are unsure which chain slugs are valid.",
  "input_schema": { "type": "object", "properties": {} }
}

import Anthropic from '@anthropic-ai/sdk'

const client = new Anthropic()

// ── Tool implementations ────────────────────────────────────────────────────

async function createPaymentLink(args) {
  const res = await fetch('https://api.stablc.xyz/v1/payment-links', {
    method:  'POST',
    headers: { 'Content-Type': 'application/json' },
    body:    JSON.stringify(args),
  })
  return res.json()  // { url, secret }
}

async function getPaymentLink({ id, secret }) {
  const res = await fetch(`https://api.stablc.xyz/v1/payment-links/${id}`, {
    headers: { Authorization: `Bearer ${secret}` },
  })
  return res.json()
}

async function getSupportedChains() {
  return fetch('https://api.stablc.xyz/v1/chains').then(r => r.json())
}

// ── Agent loop ──────────────────────────────────────────────────────────────

async function runAgent(userMessage) {
  const tools = [
    /* paste the three tool definitions here */
  ]

  const messages = [{ role: 'user', content: userMessage }]

  while (true) {
    const response = await client.messages.create({
      model:      'claude-opus-4-6',
      max_tokens: 1024,
      tools,
      messages,
    })

    messages.push({ role: 'assistant', content: response.content })

    if (response.stop_reason === 'end_turn') {
      return response.content.find(b => b.type === 'text')?.text
    }

    // Execute tool calls
    const results = []
    for (const block of response.content) {
      if (block.type !== 'tool_use') continue

      let output
      if (block.name === 'create_payment_link')   output = await createPaymentLink(block.input)
      if (block.name === 'get_payment_link')       output = await getPaymentLink(block.input)
      if (block.name === 'get_supported_chains')   output = await getSupportedChains()

      results.push({ type: 'tool_result', tool_use_id: block.id, content: JSON.stringify(output) })
    }

    messages.push({ role: 'user', content: results })
  }
}

// Example
const reply = await runAgent(
  'Create a 50 USDC payment link on ethereum-sepolia to wallet 0xYourAddress, valid until 2026-06-01. Label it "Invoice #42".'
)
console.log(reply)