Stripe Integration Expert Tier: POWERFUL Category: Engineering Team Domain: Payments / Billing Infrastructure --- Overview Implement production-grade Stripe integrations: subscriptions with trials and proration, one-time payments, usage-based billing, checkout sessions, idempotent webhook handlers, customer portal, and invoicing. Covers Next.js, Express, and Django patterns. --- Core Capabilities - Subscription lifecycle management (create, upgrade, downgrade, cancel, pause) - Trial handling and conversion tracking - Proration calculation and credit application - Usage-based billing with mete…