API.md

GOAT Flow API Compatibility Page

This root-level file is retained so existing repository and package links keep working. The canonical API documentation now lives under docs/.

Use:

• API Reference for endpoints, HMAC signing, request/response shapes, status values, QuickPay, MPP, and error semantics.
• Developer Quick Start for a first working integration.
• Integration Guide for SDK boundaries, fulfillment, retries, and production guidance.
• Hosted Checkout for product and session checkout.
• GOAT Flow MPP Integration for the independent MPP protocol boundary and this deployment's paid-route and receipt profile.

Compatibility notes:

• Published packages use the goatflow-* names listed in docs/README.md.
• Protocol fields, JSON keys such as the goatx402 extension, and GOATX402_* environment variables retain their existing technical names.
• Merchant API credentials and HMAC signing belong on the backend.
• HTTP 402 is an expected success only for endpoints documented as payment challenges, including order creation and the GOAT Flow profile's MPP challenge endpoint. This does not redefine the standard MPP HTTP exchange.
• Runtime challenge, manifest, merchant, and portal configuration is authoritative for enabled chains, tokens, limits, fees, and capabilities.

Do not copy API schemas from historical revisions of this file. Update the canonical API Reference instead.