Pre launch security and scalability checks

Seeking a mid-level developer to perform pre-launch security and scalability assessments of a React/TypeScript/Supabase web app. Responsibilities include hands-on evaluation of Supabase Row Level Security policies, OWASP Top 10 vulnerabilities, secure review of payment webhook flows, and audit of DigitalOcean gateway and third-party API integrations. Deliverables: concise vulnerability report, remediation recommendations, and scalable performance guidance. Fixed-price engagement. Full brief available.