What is GraphQL?
GraphQL is a query language for your API. Facebook made it a replacement for REST APIs, which are usually used to get information from servers. In a GraphQL API, the client specifies the data it needs in a query.
The server then returns the requested data, which can be more efficient than a REST API because the server is not returning more data than the client needs. GraphQL lets the client say how the data it needs should look, so the server can send back precisely what the client asked for.
This makes it easy for the client to get the data it needs without having to make multiple API calls or handle additional data that it doesn’t need.
Why do we need GraphQL?
Imagine you are building a social media application, and you have a REST API that allows users to retrieve their feeds of posts from their friends. You have a GET endpoint as /feed that returns a list of post objects, each with a message, likes, and comments field.
With a REST API, you might retrieve the feed like this:
# GET /feed
[
{
"message": "Hello, world!",
"likes": 10,
"comments": [
{ "message": "Great post!" },
{ "message": "I agree!" }
]
},
{
"message": "I love GraphQL!",
"likes": 5,
"comments": [
{ "message": "Me too!" },
{ "message": "I'm learning it now." }
]
}
]
