What is GraphQL

Developed by Facebook
A query language for APIs
- User-friendly because the data format of API requests and responses are similar
REST is an architecture (design), while GraphQL is a language (DSL)

Comparison of REST API and GraphQL

REST API Format

Send requests to endpoints using HTTP verbs

curl https://api.bmf-tech.com/v1/configs

[
    {
        "id": 1,
        "name": "title",
        "alias_name": "Title",
        "value": "bmf-tech",
        "created_at": "2017-09-25 23:08:23",
        "value": "bmf-tech",
        "deleted_at": null
    }
]

GraphQL API Format

Send queries to a single endpoint

curl https://api.bmf-tech.com/api

configs {
  id,
  name,
  alias_name
  value,
  created_at,
  updated_at,
  deleted_at
}

[
    {
        "id": 1,
        "name": "title",
        "alias_name": "Title",
        "value": "bmf-tech",
        "created_at": "2017-09-25 23:08:23",
        "value": "bmf-tech",
        "deleted_at": null
    }
]

	REST API	GraphQL
Endpoints	Multiple	Single
HTTP Verbs	Dependent	Independent
Type System	None	Available
Versioning Required	Yes	No
Documentation Required	Yes	No
Resource Limitation	Mainly call count	Handled according to resource amount

Flexibly specify the desired data for a single endpoint
- REST has fixed response data for each endpoint.
- GraphQL allows specifying the desired data for a single endpoint to get the response data.
Resource limitation requires ingenuity
- Handled according to resource amount
- Need to consider methods for load calculation, such as based on the number of objects
Almost no need for documentation
- API definition serves as documentation
  - The query structure and response data structure are almost the same

Points of Concern

Dependency on libraries
- Requires libraries for parsing queries
Not necessarily better performance than REST API
- Reduces the number of requests
- Increases the amount of data per request
- Need to control data volume in both REST API and GraphQL (e.g., pagination, field specification)
Monitoring
- REST API can be monitored per endpoint
- GraphQL is a single endpoint, making it difficult to monitor response performance per query. Some measures are needed.
  - Wait for ecosystem maturity or implement in-house
Caching
- Cannot use HTTP cache
- Should investigate various other aspects

Impressions

In applications with many components and complex UIs, where the number of requests increases and the client side struggles, there may be benefits to introducing it.
Considered using it with Rubel, but decided against it as it feels premature. Currently unnecessary.