# 08 — Billing (MVP: Event Credits)

- Model: one-off purchases that grant event credits; no subscriptions in MVP.
- Tables: `event_purchases`, `event_credits_ledger` (see 04-data-model-migrations.md).
- Providers: Stripe (server-side checkout + webhooks); store receipts deferred.
- Idempotency: purchase intents keyed; ledger writes idempotent; retries safe.
- Limits: enforce `event_credits_balance >= 1` to create an event; ledger decrements on event creation.