Explanation: Architected a secure API gateway layer for a headless commerce startup. This custom middleware (deployed on Vercel Edge with Next.js) orchestrates data between the Shopify GraphQL API, Stripe Payments, and a Supabase DB. Optimized a critical database query that reduced product page load times by 40%. The result is a secure, extremely fast checkout experience that handles high traffic spikes without latency, directly impacting customer conversion metrics.