GraphQL vs REST: Complete Comparison Guide

"Should we use GraphQL or REST?" This is the question I hear most from teams building new APIs. The answer? It depends. I've built production APIs with both, and each shines in different scenarios. REST isn't dead, and GraphQL isn't always better. Let me show you when to use each.

The Core Differences

Feature	REST	GraphQL
Data Fetching	Multiple endpoints, over-fetching	Single endpoint, precise data
Learning Curve	Easy, well-known	Steeper, new concepts
Caching	HTTP caching, CDN-friendly	Complex, needs custom solutions
Versioning	URL-based versions	Schema evolution, no versions
Type Safety	Optional (OpenAPI)	Built-in, strongly typed

When GraphQL Wins

// REST: Multiple requests for related data
const user = await fetch('/api/users/123').then(r => r.json());
const posts = await fetch(`/api/users/${user.id}/posts`).then(r => r.json());
const comments = await fetch(`/api/posts/${posts[0].id}/comments`).then(r => r.json());
// 3 network requests!

// GraphQL: One request, exactly what you need
const query = `
  query {
    user(id: "123") {
      name
      email
      posts {
        title
        comments {
          text
          author {
            name
          }
        }
      }
    }
  }
`;

const data = await fetch('/graphql', {
  method: 'POST',
  body: JSON.stringify({ query }),
  headers: { 'Content-Type': 'application/json' }
}).then(r => r.json());
// 1 request, nested data, no over-fetching!

GraphQL Security: The Hidden Dangers

GraphQL's flexibility is both its strength and its security nightmare. The same feature that lets clients request exactly what they need also lets attackers craft queries that bring down your entire system. I've personally responded to incidents where a single malicious GraphQL query consumed all server resources and crashed production.

The problem is query depth and complexity. In REST, you control what data each endpoint returns. In GraphQL, clients control the query structure. An attacker can nest queries deeply, create circular references through your schema, or request thousands of related objects in a single query. Your server happily tries to fulfill the request, spawning database queries that never finish, consuming memory until the process crashes.

Here's a real attack I've seen: an attacker discovered a GraphQL API with related user and post objects. They crafted a query requesting all users, each user's posts, each post's comments, each comment's author (which cycles back to users), and nested this pattern 20 levels deep. One HTTP request triggered millions of database queries. The server locked up completely within seconds. No rate limiting helped because it was technically just one request.

Authorization is another minefield. In REST, you secure endpoints. In GraphQL, you must secure every field in your schema. Miss one field authorization check, and attackers can access it through any query path. I audited a GraphQL API where the user's email field wasn't properly secured. Even though the user profile endpoint required authentication, attackers could query it through related objects (posts → author → email) and harvest email addresses for the entire user base.

Query Depth and Complexity Limiting

// Limit query depth to prevent nested attacks
const depthLimit = require('graphql-depth-limit');

const server = new ApolloServer({
  typeDefs,
  resolvers,
  validationRules: [depthLimit(5)] // Max 5 levels deep
});

// Limit query complexity
const { createComplexityLimitRule } = require('graphql-validation-complexity');

const complexityLimit = createComplexityLimitRule(1000, {
  onCost: (cost) => {
    console.log('Query cost:', cost);
  }
});

const server = new ApolloServer({
  validationRules: [complexityLimit]
});

Field-Level Authorization

// Secure EVERY field, not just queries
const resolvers = {
  User: {
    email: (user, args, context) => {
      // Check if user can see this email
      if (context.user.id !== user.id && !context.user.isAdmin) {
        throw new Error('Unauthorized');
      }
      return user.email;
    },
    ssn: (user, args, context) => {
      // Admins only
      if (!context.user.isAdmin) {
        return null; // or throw error
      }
      return user.ssn;
    }
  }
};

Migration Strategy

// Gradual migration: Wrap REST in GraphQL
const { RESTDataSource } = require('apollo-datasource-rest');

class UsersAPI extends RESTDataSource {
  constructor() {
    super();
    this.baseURL = 'https://api.example.com/';
  }

  async getUser(id) {
    return this.get(`users/${id}`);
  }

  async getPosts(userId) {
    return this.get(`users/${userId}/posts`);
  }
}

// GraphQL resolvers call REST API
const resolvers = {
  Query: {
    user: (_, { id }, { dataSources }) => {
      return dataSources.usersAPI.getUser(id);
    }
  },
  User: {
    posts: (user, _, { dataSources }) => {
      return dataSources.usersAPI.getPosts(user.id);
    }
  }
};

✅ Decision Checklist

Choose REST when:

• Simple CRUD operations
• Heavy caching requirements
• Public API for third parties
• Team unfamiliar with GraphQL

Choose GraphQL when:

• Complex, nested data relationships
• Multiple client types (web, mobile, etc.)
• Rapid frontend iteration needed
• Strong typing requirements

👥

About the Team

Written by DevMetrix's API architects with experience building both REST and GraphQL APIs at scale for Fortune 500 companies and high-growth startups.

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GraphQL vs REST: Choosing the Right API Architecture