backend-codelisted

# Backend Code Skill This skill handles backend service development, data processing, and integration. ## When to use this skill - When building APIs, workers, or microservices. - When interacting with databases, caches, and message queues. - When implementing business logic and validation rules. ## Guidelines - Validate and sanitize all incoming data at the API edge. - Assume network calls and database queries will occasionally fail; implement retries and circuit breakers. - Decouple business logic from the transport layer (e.g., Controllers should not contain complex logic). - Log structured data (JSON) and ensure PII is masked.