GraphQL vs JSON API: What are the differences?

Introduction

GraphQL and JSON API are two popular technologies used for building APIs. While both serve the same purpose of facilitating communication between clients and servers, there are key differences between them. This article will outline and explain six important distinctions between GraphQL and JSON API.

1. Query Language vs Specification: The fundamental difference between GraphQL and JSON API lies in their approach to data retrieval. GraphQL is a query language that allows clients to request the specific data they need, and the server responds with only that data. On the other hand, JSON API is a specification that defines how the server should structure its responses, regardless of what the client requested.

2. Flexibility vs Conformance: GraphQL offers more flexibility to clients as they can request any combination of data attributes in a single query, and the server responds accordingly. In contrast, JSON API follows a standardized structure where clients are limited to requesting predefined data structures. This provides consistency but sacrifices some flexibility.

3. Over-fetching and Under-fetching: In traditional RESTful APIs, clients often face the problem of over-fetching or under-fetching data, resulting in inefficiency. GraphQL solves this issue by enabling clients to request precisely the data they need, eliminating over-fetching and under-fetching problems. JSON API, while avoiding over-fetching, may still suffer from under-fetching as clients are restricted to predefined data structures.

4. Single Endpoint vs Multiple Endpoints: GraphQL operates on a single endpoint, meaning clients make a single request to fetch all the required data. In contrast, JSON API typically requires multiple requests to multiple endpoints to retrieve related resources. This difference reduces network overhead and improves performance in GraphQL.

5. Nested vs Flat Structures: GraphQL allows clients to query and receive nested data structures, reducing the number of requests needed for related data. JSON API, on the other hand, typically employs a flat structure where related resources are represented as separate entities, requiring additional requests from clients to retrieve them.

6. Strong Typing and Validation: GraphQL comes with a strong type system that defines the structure of the data and provides validation at compile time. This helps catch errors early and promotes reliable client-server communication. JSON API relies on external tools or libraries for validation and does not have built-in support for strong typing.

In summary, GraphQL and JSON API differ in their approach to data retrieval, flexibility, request efficiency, structure, and data validation. While GraphQL offers a more flexible and efficient way to query data with a single endpoint, JSON API provides a standardized structure that ensures consistency but sacrifices some flexibility.