How can GraphQL improve your web API queries?

GraphQL is a query language and a runtime system for web APIs that allows you to specify exactly what data you want from the server. It can improve your web API queries in several ways, such as reducing over-fetching, simplifying data fetching, enabling real-time updates, and facilitating schema evolution. In this article, you will learn how GraphQL works and how it can benefit your web development projects.

1 What is GraphQL?

GraphQL is a way of describing the data you need from a web API using a syntax that resembles JSON. You can write queries that specify the fields, arguments, and directives you want from the server, and get a response that matches your query structure. GraphQL also allows you to define the types and relationships of the data you expose through the API, using a schema language that is human-readable and machine-verifiable. GraphQL is not tied to any specific database or technology, and can be implemented on any server that supports HTTP.

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Bruno Medeiros Costa

Tech Lead | Desenvolvedor Full Stack | Especialista React | TypeScript | Node.js | Go Lang | Blockchain
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GraphQL is a query language and API development paradigm that values precision on a tailored level. Instead of following the traditional REST model, where multiple requests might lead to excessive data, GraphQL enables clients to gather exactly the desired information, promoting efficiency in client-server communication. With its flexible structure, developers can define custom types, thereby creating smarter and leaner APIs, enhancing the data consumption and development experience.

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2 How does GraphQL reduce over-fetching?

One of the common problems with traditional web APIs based on REST or SOAP is that they often return more data than you need, or require multiple requests to get all the data you need. This can lead to wasted bandwidth, slow performance, and complex code. GraphQL solves this problem by letting you request only the data you need, and nothing more. For example, if you want to get the name and email of a user, you can write a simple query like this:

query {
  user(id: "123") {
    name
    email
  }
}

The server will return only the name and email of the user with the given id, and nothing else. You can also use aliases, fragments, variables, and directives to customize your queries and avoid repetition.

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Bruno Medeiros Costa

Tech Lead | Desenvolvedor Full Stack | Especialista React | TypeScript | Node.js | Go Lang | Blockchain
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GraphQL reduces over-fetching by enabling clients to request specific data, preventing unnecessary information retrieval common in REST APIs. Unlike REST with fixed endpoints, GraphQL lets clients shape responses through queries, fetching only what's needed. This saves data transfer, enhancing performance.

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3 How does GraphQL simplify data fetching?

Another advantage of GraphQL is that it allows you to fetch data from multiple sources and resources with a single request. You can write queries that span across different entities and fields, and get a nested response that reflects the shape of your data. For example, if you want to get the name, email, and posts of a user, you can write a query like this:

query {
  user(id: "123") {
    name
    email
    posts {
      title
      content
    }
  }
}

The server will return the name, email, and posts of the user with the given id, and each post will have its own title and content. You don't need to make separate requests for each resource, or join them manually in your code.

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Bruno Medeiros Costa

Tech Lead | Desenvolvedor Full Stack | Especialista React | TypeScript | Node.js | Go Lang | Blockchain
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More semantically, graphql facilitates the way to request data and bring only what is necessary to the client, thus avoiding excessive searches for unnecessary data

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4 How does GraphQL enable real-time updates?

GraphQL also supports real-time updates through subscriptions, which are a way of listening to events on the server and getting notified when something changes. You can write subscriptions that specify the data you want to receive when an event occurs, and use a WebSocket connection to communicate with the server. For example, if you want to get notified when a new post is added by a user, you can write a subscription like this:

subscription {
  postAdded(userId: "123") {
    title
    content
  }
}

The server will send you the title and content of the new post whenever a post is added by the user with the given id. You can use subscriptions to implement features like live chat, notifications, or real-time dashboards.

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5 How does GraphQL facilitate schema evolution?

GraphQL also makes it easier to evolve your web API schema over time, without breaking existing clients or requiring versioning. You can add new fields, types, and directives to your schema, and they will be available to your clients immediately. You can also mark fields as deprecated, and they will be hidden from the documentation and tools, but still work for backward compatibility. GraphQL also provides introspection, which is a way of querying the schema itself and getting information about its types, fields, and directives. You can use introspection to build tools that help you explore, test, and document your web API.

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6 How can you get started with GraphQL?

If you are interested in learning more about GraphQL and how to use it in your web development projects, there are many resources and tools available online. You can start by reading the official documentation, which explains the basics of the query language, the schema language, and the runtime system. You can also use online playgrounds, such as GraphQL Playground or GraphiQL, to write and execute queries against mock or real servers. You can also find libraries and frameworks that help you implement GraphQL on different platforms and languages, such as Apollo, Relay, GraphQL.js, or GraphQL Ruby.

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7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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David G.

Senior Software Engineer | Backend Developer @ Basetis
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It would also be interesting to talk about GraphQL mutations. A GraphQL mutation is a way to modify the data on the server-side, such as creating, updating, or deleting records. A mutation is similar to a query, except that it uses the keyword mutation instead of query, and it can take arguments and return values. Here is a simple example of a mutation that creates a new user: mutation { createUser(name: "David", email: "david@example.com") { id name email } } This mutation takes two arguments: name and email, and returns the id, name, and email of the created user. The mutation name (createUser) and the arguments and return values depend on the schema definition of the GraphQL server.

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How can GraphQL improve your web API queries?

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1 What is GraphQL?

2 How does GraphQL reduce over-fetching?

3 How does GraphQL simplify data fetching?

4 How does GraphQL enable real-time updates?

5 How does GraphQL facilitate schema evolution?

6 How can you get started with GraphQL?

7 Here’s what else to consider

Web Development

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How can GraphQL improve your web API queries?

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1 What is GraphQL?

2 How does GraphQL reduce over-fetching?

3 How does GraphQL simplify data fetching?

4 How does GraphQL enable real-time updates?

5 How does GraphQL facilitate schema evolution?

6 How can you get started with GraphQL?

7 Here’s what else to consider

Web Development

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