web-production-77376.up.railway.app

The only order endpoint. Fully agent-native: no registration, no saved card, no API key. x402 flow: 1. POST with { sku, name, email, address } and no payment header — the server returns 402 with a Payment-Required header carrying accepts[] (network, USDC asset, amount in smallest units, payTo). An unpaid probe is answered with 402 regardless of body completeness; full body validation runs on the PAID retry, before settlement, so an invalid body returns 400 and no USDC is captured. 2. Sign an EIP-3009 transferWithAuthorization with your Base wallet and retry the same request with the payment header (PAYMENT-SIGNATURE for x402 v2, or X-PAYMENT for v1). 3. On 201 the Shopify order is created and USDC settles on Base. Read price/network/asset/payee from the 402 envelope — do not hard-code. Payment uses deferred capture: USDC is captured only after a 2xx, and cancelled on 4xx/5xx. A 502 means no USDC was captured (safe to retry). Idempotency is keyed on the payment nonce — replaying the same signed authorization returns your original order (200), not a duplicate. Promo flow: include promo_code (with no payment header) for a free order. Do not send both a promo_code and a payment header. Collect the recipient's real name, email, and shipping address from the human — do not guess. All validation runs before payment settles, so a malformed body returns 400 with no charge.