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Top 10 GraphQL API Mistakes and Best Practices

4 min readFeb 13, 2025

GraphQL is a powerful query language that provides flexibility, efficiency, and developer-friendly APIs. However, if not implemented correctly, it can lead to security vulnerabilities, performance bottlenecks, and maintainability issues.

In this article, we’ll explore the top 10 GraphQL API mistakes and how to avoid them using best practices.

1️⃣ Exposing All Data Without Proper Authorization 🔓

❌ Mistake: No Access Control for Sensitive Data

GraphQL allows clients to request exactly what they need, but if you don’t secure it properly, users might access unauthorized data.

Bad Example: ❌

type Query {
    users: [User]
}

type User {
    id: ID
    email: String
    password: String
    role: String
}

✔ Issue: Anyone can query all users, including passwords!

✅ Solution: Use Role-Based Access Control (RBAC)

Implement authentication & authorization checks in resolvers.
Use libraries like graphql-shield (for Node.js).

✔ Good Example (Applying Authorization Middleware) ✅

const resolvers = {
  Query: {
    users: (parent, args, context) => {
      if (!context.user || context.user.role !== "ADMIN") {
        throw new Error("Unauthorized");
      }
      return getUsers();
    },
  },
};

✔ Best Practices:

Validate user roles in resolvers.
Use GraphQL directives for access control.

2️⃣ Allowing Unrestricted Queries (Denial-of-Service Risk) 🛑

❌ Mistake: No Query Depth or Complexity Limiting

Clients can ask for deeply nested queries, overloading the server.
Example: A single request like this can crash your API.

query {
    users {
        friends {
            friends {
                friends {
                    email
                }
            }
        }
    }
}

✔ Issue: Unrestricted deep queries can cause a performance hit.

✅ Solution: Implement Query Depth and Complexity Limits