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GraphQL is a powerful query language tool. It enables developers to work more efficiently and flexibly with APIs. There are several officially supported implementations in various languages. The key difference is that this language uses a type system that allows you to create a schema for your API. With this, you can validate the queries made by the application to determine what was requested and return exactly what was requested—nothing more, nothing less. In practical terms, this means you can request only the fields you need from an endpoint.
Without a doubt, GraphQL is the new hype of the moment, and surely you’ve heard that it’s coming to dominate the world of API creation, right? Very interesting and useful, GraphQL serves as a helping hand when creating an API that needs to be modified to return more or less data, more or fewer relationships, etc. It’s undoubtedly a technology that’s spreading rapidly.
GraphQL is a tool based on data requests—a query language—and allows you to be very specific. But how? It also allows you to execute mutations, which are responsible for inserting and modifying data.
What Can You Do with APIs?
APIs allow your company’s technologies to communicate and work together more efficiently. Technologies that don’t communicate with each other or with third-party solutions waste time and money.
API (application programming interface) is one of the most basic tools used in web and mobile application programming. Using HTTP, they ensure communication between the client and the server, and at the same time allow for the extension of the functionality of the given tool and the automation of specific procedures. The REST architecture is now standardly used for this purpose, but it has been following the footsteps of the so-called GraphQL for some time.
What Is GraphQL?
GraphQL is a query language (not a programming language) that is a direct competitor and successor to REST API solutions. It offers a more efficient approach to creating application programming interfaces (APIs) and has greatly influenced the style in which applications such as React are written.
GraphQL technology first appeared on the market in 2012 in connection with the development of the native Facebook application and is therefore the original creation of the development team of this, currently, the most widespread social network. In 2015, Facebook released it as an open-source solution, causing its massive expansion across the entire market.
Gradually, more organizations, including GitHub, Shopify, and the social network Pinterest, have decided to adopt this approach to creating modern APIs.
It uses only one endpoint and dynamically changing data. This means that only one query is sent for the desired result. The response is then adapted to the structure of this query. The query format defines the response format. Therefore, the client always receives the expected output and only the data that was requested.
The main purpose of using GraphQL is to better structure APIs for mobile and other applications.
GraphQL Features
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GraphQL can separate front-end from back-end development
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Helps save bandwidth
GraphQL Architecture
The GraphQL architecture is built on several core features that define its use. These include:
Hierarchy – Fields are arranged into a hierarchical set, which allows you to always work with only a specific subset. The server always works with all data but only sends back the data requested by the client.
Product orientation – The form of the query or response is not specified by the server but by the client, which determines the amount and format of transmitted data.
Strong typing – GraphQL has a specific type system. Queries are validated before they are sent to the server, eliminating potential errors and saving computing power.
Introspection – Developers can ask questions about the types supported by the server, making it easier to explore a specific GraphQL API.
GraphQL technology also simplifies versioning. It is a non-versioned query language. Newly added features extend functionality without affecting the original.
Basic GraphQL Concepts
One of the basic concepts related to the use of GraphQL is the schema. The schema acts as an intermediary between the frontend and the backend, and all passing queries are validated on its basis. It is necessary to create and maintain a clear GraphQL schema that defines all related items. The schema is built using the SDL language.
Another concept is queries, which specify the data to be worked with and determine the form of the returned response. A useful feature is fragments, used for declaring and calling repetitive parts of code.
Mutations are used for writing and modifying data. They occur in three forms—create, update, and delete—and can also return values created on the server.
Subscriptions are useful for real-time applications and can be linked to backend events, such as displaying a list of comments.
Meet GraphQL
It allows us to validate any type of API built with GraphQL through features such as:
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Syntax highlighting
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Auto complete
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Real-time error management and reporting
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Management and execution of queries and results
GraphQL Usage and Syntax Example
The general principle of API operation is based on client-server interaction. For example, a user visits a blog via a web browser and wants to share it on Twitter. The Twitter API is called, and the response contains information about the author, articles, and comments. This may also download unnecessary data.
GraphQL Online
For better understanding, you can try GraphQL using the GraphiQL tool online. An example API endpoint is available and can be modified by specifying any path. GraphiQL can also be used for testing and validation of GraphQL APIs.
GraphQL API vs. REST API
The difference can also be seen in defining resources and their structure for clients. In REST API, this task lies with the server. The client receives all the data and has to adapt when it changes.
With GraphQL, this task falls on the client. The client determines the format of the received and sent data and retrieves it from a single nested structure. By not working with data that it does not directly need, it can avoid more complex operations and reduce computing power requirements.
There is no so-called over-fetching, i.e. downloading excess data and overloading the system. REST API also reacts less well to changes in the frontend, and there is always a risk that related operations will slow down.
REST Architecture
REST is an interface architecture for distributed systems. It is closely related to HTTP and is data-oriented. This means that it specifies the ways in which data can be accessed. REST separates the client and server parts, which makes it platform-independent, like GraphQL, and allows for independent server and client development.
To reduce latency, REST uses a cache, a memory that stores queries when large amounts of data are requested or before they are used again. Data must be marked as either cacheable or non-cacheable. If it is cacheable, the system assumes that it will be used in the future and leaves it in the cache.
This improves performance on the client side but increases the chance of information becoming outdated.
Advantages and Disadvantages of GraphQL
The documentation for GraphQL technology specifies usage at three levels. The first is working with any database, the second option is GraphQL acting as an intermediate layer between existing systems. It can therefore be deployed on top of the current REST API and used as a tool for simple addressing. In the case of an existing solution, it is therefore not necessary to redo the entire implementation. The last option is a combination of both solutions.
The advantages of GraphQL have already been evident from the original architecture specification. The main advantage is the speed and stability of the application, caused by the client-side query specification—it always receives only the data it requests, and nothing extra is transferred. Data from several sources is displayed in one place thanks to the hierarchical arrangement. The application thus remains agile even on weaker mobile connections (EDGE).
The type system ensures that data is validated before the query is executed. This saves computing power that would otherwise be spent on a non-existent request or a syntax error. In short, switching to GraphQL reduces traffic between the frontend and the API.
The disadvantages of GraphQL include caching issues, for which there is currently no specific specification to address. It can also be problematic when entering long and complex queries. Most of the overhead remains on the server side, which increases the requirements for its management.
Schemas, Resolvers, Queries, and Other Common GraphQL Terms
Are you wondering which technology package is the best solution for your next project? The choice can be difficult for many reasons. You have four options to choose from: SOAP, gRPC, REST, and GraphQL. However, the two most commonly considered options in the development community are the better-known REST API and the newer GraphQL.
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