# PayOptimum / PayFlow — AI Website Builder Quickstart

Full human reference: https://payoptimum.org/developer-docs
Machine manifest: https://payoptimum.org/.well-known/payoptimum-ai-builder.json
On-demand complete reference: https://payoptimum.org/llms-full.txt

## Pick one product
- **PAYFLOW_NATIVE_AURORA**: native PayFlow checkout; Aurora Classic or Pro V7.
- **STRIPE_ADAPTER_V4**: add-on for merchants already using their own Stripe account. Stripe processes their customer payments. PayFlow charges a separate 39 EUR/month product subscription.
- **Never merge** the above processors, API routes, credentials, ledgers or transaction statuses.

## Build safely
1. Identify the merchant website stack and selected product.
2. Default to **TEST**. Obtain the actual deployed API contract; never guess paths.
3. Add responsive checkout UI, but keep card handling in approved hosted fields.
4. Authenticate merchant server-side; load price, currency and order from trusted store.
5. Generate idempotent checkout creation server-side; no secrets sent to browser.
6. Verify provider-specific signed webhooks, replay protection, status and tenant isolation.
7. Mark paid only from verified provider evidence, never success redirect.
8. Test unauthorized merchant, duplicate event, timeout, failures and rollback.
9. Require explicit LIVE authorization, including server-side LIVE_CLIENT_ENABLED.

## Sandbox, LIVE, billing
PayFlow Sandbox is for testing. PaymentHub (payflowbuzz-canada in the project architecture) is LIVE-only through PayFlow. The current PayOptimum Subscribe workflow records pending_billing ONLY; it does not collect, invoice or activate the product.

## Outputs for a website builder
- Merchant checkout UI and authenticated administration
- Server adapter using **verified** request/response contract
- Webhook validation, idempotency and ledger state reconciliation
- Tests (including merchant A/B isolation) and secrets inventory
- Deployment, monitoring, rollback and explicitly unverified assumptions

## Copyable instruction
> Read https://payoptimum.org/llms.txt and the AI builder JSON manifest. Choose native Aurora or Stripe Adapter V4; keep processors independent. Generate frontend, server adapter, verified webhook and negative tests. Server-resolve merchant identity and order amount, never expose keys or raw card data. Start in TEST. Do not invent API endpoints, set an order paid from a redirect, or enable LIVE without independently verified authorization.

See the human docs for full code listings, checkout state machines and operational checklists.