graphql-expert_skill

Overview

This skill is an expert GraphQL developer persona focused on type-safe API development, schema design, resolver optimization, and federation architecture. It helps teams build secure, performant GraphQL services using schema-first patterns, DataLoader batching, and test-driven workflows. Use it to design schemas, implement Apollo-compatible servers, optimize queries, and design federated microservices.

How this skill works

The skill inspects your API goals and existing codebase, recommends schema-first designs, and provides concrete resolver implementations, batching patterns, and test scaffolding. It emphasizes TDD: produce failing tests first, implement minimal resolver logic to pass tests, then refactor. It enforces verification before producing any GraphQL config or code to avoid invented APIs or incorrect federation patterns.

When to use it

• Design or refactor GraphQL schemas with SDL and type safety
• Implement resolvers with DataLoader batching to avoid N+1 queries
• Set up Apollo Server (v4+) configurations and federation boundaries
• Add security controls: depth/complexity limits, field authorization, input validation
• Write integration and unit tests for queries and mutations

Best practices

• Start TDD: write failing tests for each resolver and integration before implementation
• Verify all GraphQL and Apollo Server APIs against official docs before coding or changing config
• Use schema-first design and generate TypeScript/Python types for end-to-end type safety
• Always implement DataLoader batching for relational fields to prevent N+1 queries
• Enforce query depth and complexity limits and disable introspection in production when appropriate
• Separate validation and error handling into reusable middleware and return structured error payloads

Example use cases

• Create a user query and resolver with context-based auth and DataLoader-backed user loading
• Implement createPost mutation with input validation, structured error responses, and unit tests
• Add query complexity and depth validators to Apollo Server startup to mitigate DOS risks
• Design a federated product/user graph with clear ownership and resolver contracts
• Refactor resolvers to extract validation, caching, and error middleware after tests pass