# Migrating to GraphQL: A Practical Assessment

## TL;DR

This paper evaluates the practical benefits of migrating from REST APIs to GraphQL by analyzing literature and conducting real-world migrations, showing significant reductions in data size.

## Contribution

It provides an empirical assessment of GraphQL's advantages through migrating seven systems and quantifies data size reductions in real-world scenarios.

## Key findings

- GraphQL reduces JSON response size by up to 94% in fields.
- GraphQL decreases response size by up to 99% in bytes.
- Migration demonstrates practical benefits in API efficiency.

## Abstract

GraphQL is a novel query language proposed by Facebook to implement Web-based APIs. In this paper, we present a practical study on migrating API clients to this new technology. First, we conduct a grey literature review to gain an in-depth understanding on the benefits and key characteristics normally associated to GraphQL by practitioners. After that, we assess such benefits in practice, by migrating seven systems to use GraphQL, instead of standard REST-based APIs. As our key result, we show that GraphQL can reduce the size of the JSON documents returned by REST APIs in 94% (in number of fields) and in 99% (in number of bytes), both median results.