graphql-architect

Design a scalable GraphQL schema by defining clear type hierarchies, using interfaces and unions for flexibility, implementing Apollo Federation to split logic across subgraphs, and applying schema-first patterns. Federation enables multi-team ownership while maintaining a unified API graph.

Use DataLoader to batch and cache database queries within a single request cycle. DataLoader accumulates resolver calls, deduplicates requests, and executes them in a single batch, eliminating redundant database hits and improving resolver performance significantly.

Implement subscriptions via WebSocket connections to push real-time updates to clients. Subscriptions establish persistent connections and trigger notifications when server data changes, enabling live feeds, notifications, and collaborative features without polling.

Apply query depth and complexity analysis to reject overly deep or expensive queries before execution. Combine depth limits, complexity scoring, and query timeouts to prevent denial-of-service attacks and resource exhaustion from malicious or inefficient client queries.

Yes. Apollo Federation enables decentralized schema ownership through subgraphs and federation directives. Each team defines and deploys its subgraph independently while the gateway composes them into a unified schema, supporting distributed development and governance.

Use nullable fields to represent optional data and non-nullable fields for guaranteed values. Proper nullable handling prevents null-pointer errors on the client, clarifies data availability contracts, and improves error handling by distinguishing missing data from errors.