Understanding APIs: REST vs GraphQL

Introduction

In today’s interconnected digital world, APIs (Application Programming Interfaces) are the backbone of modern software development. They enable different systems—like mobile apps, web services, and third-party tools—to communicate and share data seamlessly. Among the most popular approaches to building APIs are REST and GraphQL. While both serve the same fundamental purpose, they differ significantly in design, flexibility, and use cases.

In this post, we’ll explore what REST and GraphQL are, compare their key differences, and discuss the pros and cons of each to help you decide which might be the right choice for your next project.

What is REST?

REST (Representational State Transfer) is an architectural style for designing networked applications. Introduced by Roy Fielding in 2000, REST relies on a stateless, client-server communication model, typically using HTTP protocols.

In a REST API:

• Data is organized into resources, each identified by a unique URL (endpoint).
• Standard HTTP methods like GET, POST, PUT, and DELETE are used to perform operations (CRUD: Create, Read, Update, Delete).
• Data is usually returned in JSON format (though XML and others are possible).

For example:

GET /api/users/123          → Returns user with ID 123
POST /api/users             → Creates a new user
PUT /api/users/123          → Updates user 123
DELETE /api/users/123       → Deletes user 123

REST APIs are widely adopted, well-documented, and supported by countless tools and frameworks.

What is GraphQL?

GraphQL, developed by Facebook in 2012 and publicly released in 2015, is a query language and runtime for APIs. Unlike REST, which exposes multiple endpoints, GraphQL provides a single endpoint through which clients can request exactly the data they need.

With GraphQL:

• The client specifies what data it wants in a query.
• The server responds with only that data, nothing more, nothing less.
• The schema defines the types and relationships available.

Example query:

query {
  user(id: "123") {
    name
    email
    posts {
      title
      comments {
        text
      }
    }
  }
}

This single request can fetch nested data (e.g., user + posts + comments), reducing the number of round trips compared to REST.

Key Differences Between REST and GraphQL

Pros and Cons

REST: The Tried-and-True Approach

Pros:

• ✅ Simple and predictable – Easy to understand and implement.
• ✅ Excellent caching – Leverages HTTP caching mechanisms.
• ✅ Widely supported – Works with virtually every platform and framework.
• ✅ Stateless and scalable – Ideal for distributed systems.

Cons:

• ❌ Over-fetching/under-fetching – Clients often get too much or too little data.
• ❌ Multiple round trips – Fetching related data may require several requests.
• ❌ Versioning challenges – Updating APIs often requires versioned endpoints (e.g., /v1/users).

GraphQL: The Flexible Alternative

Pros:

• ✅ Precise data fetching – Clients get exactly what they ask for.
• ✅ Fewer requests – Complex data can be fetched in a single query.
• ✅ Strong typing & introspection – Built-in schema allows for better tooling and documentation.
• ✅ Rapid frontend development – Frontend teams can iterate without backend changes.

Cons:

• ❌ Caching complexity – No native HTTP caching; requires additional setup.
• ❌ Performance risks – Poorly designed queries can overload the server (e.g., deep nesting).
• ❌ Learning curve – Requires understanding of schemas, resolvers, and query structure.
• ❌ Not ideal for simple use cases – Can be overkill for basic CRUD apps.

When to Use REST vs GraphQL?

Choose REST if:

• You need a simple, cacheable API.
• Your data structure is stable and predictable.
• You’re building public APIs or integrations with third parties.
• You want maximum compatibility and minimal setup.

Choose GraphQL if:

• Your clients need flexible, customized responses.
• You’re building complex applications with interconnected data.
• You want to empower frontend teams to fetch data independently.
• You’re dealing with multiple client types (web, mobile, IoT) with varying data needs.

Final Thoughts

REST and GraphQL aren’t mutually exclusive—they’re tools for different jobs. REST remains a solid, battle-tested choice for many applications, especially where simplicity and performance matter. GraphQL shines in dynamic environments where data requirements vary and efficiency is key.

The best approach often depends on your project’s specific needs. Some organizations even use both—GraphQL for internal or client-heavy services, and REST for external integrations.

Thank you

Big thanks for reading! You’re awesome, and I hope this post helped. Until next time!