api-response-optimization

What problem does it solve? Slow API responses and oversized payloads degrade user experience and inflate bandwidth costs. This Skill provides concrete patterns for reducing payload sizes, implementing HTTP caching, and enabling response compression in Node.js/Express APIs. ## Core Features & Use Cases - Sparse Fieldsets: Let clients request only the fields they need via query parameters (e.g., GET /users?fields=id,name,email), cutting payload size dramatically. - HTTP Caching with ETags: Generate ETag hashes and return 304 Not Modified responses so clients reuse cached data instead of re-downloading unchanged resources. - Response Compression: Enable gzip/brotli compression middleware with configurable levels and filters to shrink responses over 1KB. - Use Case: Your Express API returns 500KB user payloads with 500ms response times. Apply sparse fieldsets, ETag caching, and compression to reach the documented targets of under 100ms response times and under 50KB payloads. ## Quick Start Ask the assistant to optimize your Express API endpoints by adding sparse fieldsets, ETag caching headers, and compression middleware.