graphql-schema Skill

This skill prevents "Graph Spaghetti" and ensuring performant Graph APIs.

1. Schema Design

• Consumption-First: Design for the UI needs, not the DB schema.
• Naming: User.posts (Good), User.getPosts (Bad - it's a field, not a method).
• Nullability:
  • Default to Nullable for fields (resilience: if one field fails, partial data returns).
  • Use Non-Null (!) only for IDs and essential arguments.

2. N+1 Problem (The Graph Killer)

• Scenario: Querying users { posts { comments } }.
• Solution: DataLoader pattern.
  • Batches IDs from multiple resolvers.
  • Runs one DB query: SELECT * FROM posts WHERE user_id IN (1, 2, 3).
  • Distributes results back to resolvers.

3. Pagination

• Avoid offset/limit.
• Use Relay Connection Specification (Cursor-based):
  graphqlCopy

  users(first: 10, after: "cursor") {
    edges {
      node { name }
      cursor
    }
    pageInfo { hasNextPage }
  }
  

4. Security

• Depth Limiting: Block queries deeper than 5 levels (prevent cyclic recursion DoS).
• Cost Analysis: Assign points to fields. Block query if Cost > 1000.
• Introspection: Disable in Production.

5. Federation (Apollo)

• Use when splitting Graph across microservices.
• Entity: A type shared across subgraphs (@key(fields: "id")).
• Gateway: Composes the Supergraph.