modbender Credpay Checkout Skill
API Base URL: https://checkout-agent.credpay.xyz
Trigger this skill whenever the user wants to purchase, order, or checkout a product from any online store.
What you need from the user
Collect these before starting (ask if missing):
| Field | Example |
|---|---|
| Product URL | https://example.com/products/tee |
| Quantity | 1 |
| Size / Color (if applicable) | "Size": "M", "Color": "Black" |
customer@example.com |
|
| Goods total (USD) | "49.99" — item price as a USD string, no currency symbol |
| Shipping address | firstName, lastName, line1, city, state, postalCode, country, phone |
Step 1 — Get a quote (no payment needed)
POST https://checkout-agent.credpay.xyz/v1/quote
Content-Type: application/json
{
"items": [
{
"url": "<product URL>",
"quantity": 1,
"options": { "Size": "M", "Color": "Black" }
}
],
"email": "<email>",
"shippingAddress": {
"firstName": "Jane",
"lastName": "Doe",
"line1": "123 Main St",
"city": "Austin",
"state": "TX",
"postalCode": "78701",
"country": "United States",
"countryCode": "US",
"phone": "+15125551234"
},
"goodsTotal": "<item price in USD as string, e.g. \"49.99\">"
}
→ Save maxAmount from the response. This is the USDC amount you will pay via x402.
Step 2 — Submit checkout (x402 payment required)
POST https://checkout-agent.credpay.xyz/v1/checkout
Content-Type: application/json
X-PAYMENT: <x402 payment payload for maxAmount on Base chainId 8453>
<same body as Step 1>
→ On 202: save requestId and go to Step 3.
→ On 402: re-read the payment requirements from the response and retry with a correct X-PAYMENT header.
Step 3 — Poll for completion
GET https://checkout-agent.credpay.xyz/v1/checkout/{requestId}
Poll every 5 seconds. Stop when status is completed or failed. Timeout after 10 minutes.
| Status | Action |
|---|---|
processing |
Keep polling |
authorization_required |
See Step 4 |
completed |
Done — return result to user |
failed |
Report errorCode + errorMessage to user |
Step 4 — Handle extra payment (if needed)
If status is authorization_required, the order total exceeded the quoted amount:
POST https://checkout-agent.credpay.xyz/v1/checkout/{requestId}/authorize
X-PAYMENT: <x402 payment for extraOwed amount>
Then resume polling from Step 3.
Rules
- Works with any online store — just pass the product page URL.
- Never create a second checkout for the same intent while a
requestIdis active. - Retry transient network errors with exponential backoff. Never blind-retry
failedstatus. - Default
chainIdis8453(Base).
Success response
{
"requestId": "req_abc123",
"status": "completed",
"success": true,
"orderNumber": "1234"
}
Failure response
{
"requestId": "req_abc123",
"status": "failed",
"success": false,
"errorCode": "payment_failed",
"errorMessage": "Card declined"
}