Web Development
- React: Hooks, custom hooks, Context API, performance optimization (useMemo/useCallback), Fiber architecture, concurrent features
- Next.js 15+: App Router, Server/Client Components, SSR/SSG/ISR, Streaming, middleware, advanced caching strategies, Edge Runtime
- TypeScript: Generics, conditional/mapped types, utility types, strict type safety
- Styling: Tailwind CSS, CSS Modules, responsive design

Real-time Communication (Critical)
- WebRTC Expert: SDP exchange, ICE/STUN/TURN, RTCPeerConnection, MediaStream management, SFU architecture, simulcast/SVC
- Performance: Adaptive bitrate, packet loss handling (FEC/NACK), latency optimization, getStats monitoring
- Production: Must have shipped products with 1000+ concurrent video participants
- WebSocket: Advanced state management, reconnection strategies, message queuing, horizontal scaling
- Codecs: H.264/VP8/VP9/AV1, Opus/AAC, audio processing (echo cancellation, noise suppression)

Subscription & Payment (Critical)
- Stripe Expert: Payment Intents, Subscription API, webhooks, SCA/3D Secure, billing cycles
- Features: Trial periods, plan upgrades/downgrades with proration, dunning management, usage-based billing, multi-currency
- Security: PCI DSS compliance, secure token handling, never store card data
- UX: Self-service billing portal, invoice management, payment failure handling

User Management (Critical)
- Auth: OAuth 2.0, JWT with refresh tokens, MFA, magic links, Apple/Google Sign-In
- Authorization: RBAC implementation, hierarchical roles (admin/teacher/student), permission systems, feature flags
- Security: Secure hashing (bcrypt/Argon2), CSRF protection, rate limiting, account lockout
- Multi-tenancy: Organization/school structure, team invitations, role assignment, resource ownership
- Compliance: GDPR (data export/deletion), audit logging

Backend Integration
- RESTful/GraphQL APIs, WebSocket integration, JWT/OAuth 2.0, error handling with retry logic
- Debugging: Chrome DevTools, Postman, Charles
- Python/TypeScript backend familiarity (bonus)

AI-Assisted Development
- Cursor, Claude Code proficiency
- Strategic use of Claude 4.5, Gemini 2.5 Pro, ChatGPT-5
- Clear boundaries: AI for boilerplate, human control for architecture/security/performance