How do you optimize NestJS application performance for high traffic?

NestJS performance optimization strategies: Use Fastify instead of Express as the HTTP adapter — Fastify is significantly faster. Avoid REQUEST scope for providers that do not need per-request state — use singletons and AsyncLocalStorage for shared context. Enable response caching with Redis for expensive, infrequently changing endpoints. Use database connection pooling and avoid N+1 queries with eager loading or DataLoaders. Enable compression middleware. Use cluster mode (PM2 or Node.js cluster) to utilize all CPU cores. Lazy-load modules with LazyModuleLoader to reduce startup time and memory for large applications. Profile with clinic.js or Node.js built-in profiler to identify bottlenecks. Use streams for large file responses. Implement circuit breakers for external service calls to prevent cascading failures.