Online Payments & TipJar Integration

The default full build (payments Cargo feature) includes pure-Rust cryptographic payment gateways for WeChat Pay v3, Alipay, and Stripe — with no external billing microservice required.

End-to-End Fulfillment Guarantees

1. Idempotent Order State Machine: Orders transition strictly forward (Pending -> Paid -> Fulfilled);
2. Asymmetric Webhook Verification: Every /api/pay/*/notify callback verifies provider signatures and exact order amounts on the server;
3. Transactional Entitlement Granting: Verified callbacks mark the order paid and insert the user's course or Pro membership entitlement inside a single PostgreSQL transaction;
4. Reader TipJar (TipJar): Blog posts and podcast episodes display a lightweight support card when compiled with payments, and strip all payment routes and UI cleanly in basic, accounts, and course builds.