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CTRL K
System
GraphQL
=======
### Describe your data
type Project {
name: String
tagline: String
contributors: [User]
}
### Ask for what you want
{
project(name: "GraphQL") {
tagline
}
}
### Get predictable results
{
"project": {
"tagline": "A query language for APIs"
}
}
[Get Started](/learn/)
A query language for your API
-----------------------------
GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. GraphQL provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools.
Ask for what you need,
get exactly that
-----------------------------------------
Send a GraphQL query to your API and get exactly what you need, nothing more and nothing less. GraphQL queries always return predictable results. Apps using GraphQL are fast and stable because they control the data they get, not the server.
Query
{
hero {
name
height
mass
}
}
Response
{
"hero": {
"name": "Luke Skywalker",
"height": 1.72,
"mass": 77
}
}
Get many resources
in a single request
----------------------------------------
GraphQL queries access not just the properties of one resource but also smoothly follow references between them. While typical REST APIs require loading from multiple URLs, GraphQL APIs get all the data your app needs in a single request. Apps using GraphQL can be quick even on slow mobile network connections.
{
hero {
name
friends {
name
}
}
}
{
"hero": {
"name": "Luke Skywalker",
"friends": [
{ "name": "Obi-Wan Kenobi" },
{ "name": "R2-D2" },
{ "name": "Han Solo" },
{ "name": "Leia Organa" }
]
}
}
Describe what's possible
with a type system
---------------------------------------------
GraphQL APIs are organized in terms of types and fields, not endpoints. Access the full capabilities of your data from a single endpoint. GraphQL uses types to ensure Apps only ask for what's possible and provide clear and helpful errors. Apps can use types to avoid writing manual parsing code.
Query
{
hero {
name
friends {
name
homeWorld {
name
climate
}
species {
name
lifespan
origin {
name
}
}
}
}
}
Schema
type Query {
hero: Character
}
type Character {
name: String
friends: [Character]
homeWorld: Planet
species: Species
}
type Planet {
name: String
climate: String
}
type Species {
name: String
lifespan: Int
origin: Planet
}
Move faster with powerful developer tools
-----------------------------------------
Know exactly what data you can request from your API without leaving your editor, highlight potential issues before sending a query, and take advantage of improved code intelligence. GraphQL makes it easy to build powerful tools like [Graph_i_QL](https://github.com/graphql/graphiql) by leveraging your API’s type system.
Evolve your API
without versions
----------------------------------
Add new fields and types to your GraphQL API without impacting existing queries. Aging fields can be deprecated and hidden from tools. By using a single evolving version, GraphQL APIs give apps continuous access to new features and encourage cleaner, more maintainable server code.
type Film {
title: String
episode: Int
releaseDate: String
}
type Film {
title: String
episode: Int
releaseDate: String
openingCrawl: String
}
type Film {
title: String
episode: Int
releaseDate: String
openingCrawl: String
director: String
}
type Film {
title: String
episode: Int
releaseDate: String
openingCrawl: String
director: String
directedBy: Person
}
type Person {
name: String
directed: [Film]
actedIn: [Film]
}
type Film {
title: String
episode: Int
releaseDate: String
openingCrawl: String
director: String @deprecated
directedBy: Person
}
type Person {
name: String
directed: [Film]
actedIn: [Film]
}
Bring your own data and code
----------------------------
GraphQL creates a uniform API across your entire application without being limited by a specific storage engine. Write GraphQL APIs that leverage your existing data and code with GraphQL engines available in many languages. You provide functions for each field in the type system, and GraphQL calls them with optimal concurrency.
* GraphQL
type Character {
name: String
homeWorld: Planet
friends: [Character]
}
* JavaScript
// type Character {
class Character {
// name: String
getName() {
return this._name
}
// homeWorld: Planet
getHomeWorld() {
return fetchHomeworld(this._homeworldID)
}
// friends: [Character]
getFriends() {
return this._friendIDs.map(fetchCharacter)
}
}
* Python
# type Character {
class Character:
# name: String
def name(self):
return self._name
# homeWorld: Planet
def homeWorld(self):
return fetchHomeworld(self._homeworldID)
# friends: [Character]
def friends(self):
return map(fetchCharacter, self._friendIDs)
* C Sharp
// type Character {
public class Character {
// name: String
public String Name { get; }
// homeWorld: Planet
public async Task<Planet> GetHomeWorldAsync() {
return await FetchHomeworldAsync(_HomeworldID);
}
// friends: [Character]
public async IEnumerable<Task<Character>> GetFriendsAsync() {
return _FriendIDs.Select(FetchCharacterAsync);
}
}
* GraphQL
type Character {
name: String
homeWorld: Planet
friends: [Character]
}
* JavaScript
// type Character {
class Character {
// name: String
getName() {
return this._name
}
// homeWorld: Planet
getHomeWorld() {
return fetchHomeworld(this._homeworldID)
}
// friends: [Character]
getFriends() {
return this._friendIDs.map(fetchCharacter)
}
}
* Python
# type Character {
class Character:
# name: String
def name(self):
return self._name
# homeWorld: Planet
def homeWorld(self):
return fetchHomeworld(self._homeworldID)
# friends: [Character]
def friends(self):
return map(fetchCharacter, self._friendIDs)
* C Sharp
// type Character {
public class Character {
// name: String
public String Name { get; }
// homeWorld: Planet
public async Task<Planet> GetHomeWorldAsync() {
return await FetchHomeworldAsync(_HomeworldID);
}
// friends: [Character]
public async IEnumerable<Task<Character>> GetFriendsAsync() {
return _FriendIDs.Select(FetchCharacterAsync);
}
}
Who's using GraphQL?
--------------------
Facebook's mobile apps have been powered by GraphQL since 2012. A GraphQL spec was open sourced in 2015 and is now available in many environments and used by teams of all sizes.
[](https://facebook.com)[](https://docs.github.com/en/graphql)[](https://pinterest.com)[](https://intuit.com)[](https://coursera.org)[](https://shopify.com)
[More GraphQL Users](/users/)