What is GraphQL?

GraphQL is a query language. What is a query language? Simple: query languages ​​allow you to query databases and various information systems to retrieve data. For example, you can extract very specific details about specific customers from a huge database using a query language. Let's say you want to know the last time Customer X purchased Item 1 from your online store. With the right query, you can find this information very quickly.

For example, a MySQL database query could look like this:

 SELECT column_to_select FROM table_to_select WHERE certain_conditions_apply;

This is how you query a MySQL database to retrieve specific data. This command is very limited to a specific database server (MySQL). And if you run the query incorrectly, you could end up with a lot of data to analyze. Given the idea of ​​a query is to retrieve specific data, this can become counterproductive.

That's why in 2012 Facebook started working on a query language that went beyond database servers and could work with Application Programming Interfaces (APIs). This new query language was created to ensure that clients received only the data they requested and nothing more. That query language was GraphQL, which was designed to be fast, flexible, and developer-friendly.

GraphQL is important, not just because it allows you to query an API, but also because:

• It can be integrated with your applications and services.
• Allows your applications/services to describe the exact type and format of data required from an API.
• Allows applications to call a single endpoint for a request.
• It is ideal for complex systems and even microservices.
• It does not suffer from over- or under-searching.
• Supports validation and type checking out of the box.
• Automatically generates API documentation.
• It's enterprise and production ready.
• It's very easy to learn.

The benefits of over- and under-searching cannot be overstated. With some other languages, you will find that queries will return too much or too little information. Too much and a bottleneck can occur with a connected app. If there is little data, the connected application will not have the information it needs to continue a process. Fortunately, GraphQL strikes the right balance.

How did GraphQL start?

GraphQL was started by Facebook engineers Lee Byron, Dan Schafer, and Nick Schrock. The project began because developers of Facebook's mobile project had to work with considerable amounts of nested and interconnected data. Without an efficient means of querying, the mobile version of Facebook was unable to perform acceptably. Instead, developers realized they needed to query the exact form of data for services like news feed, messages, posts, comments, and likes.

This problem has become exponentially more complicated, given the large number of users of the platform. This need led to GraphQL. What Facebook engineers created was a language that is considerably faster than the competition when communicating with APIs, because it reduces queries by choosing only selected fields. This feature makes it ideal for very complex systems and microservices. And because all queries return a simple, predictable format, GraphQL allows developers to more easily write specific queries on an as-needed basis.

In the end, Facebook developers wanted to get rid of multiple “dumb” endpoints and create a single “smart” endpoint that could accept very complex queries and then deliver the data to customers in whatever format the customer needed.

Our enterprise software development services are designed for large-scale projects. We take care of everything related to the software: from project layout to quality assurance testing and maintenance. No matter your sector or area of ​​activity, our goal is to create impactful technological solutions so that your company can generate value and achieve its goals. Contact us today and tell us about your company, your goals, and any ideas you want to turn into real software.

How does GraphQL work?

One thing to remember is that GraphQL is a syntax that describes how to request data. This syntax, in turn, extracts data from a server and loads it into a client. At the same time, GraphQL allows the customer to specify exactly what they need, makes it easy to aggregate data from multiple sources, and uses a specific type system to describe the data.

The GraphQL “layer” exists between the client and the data source, accepting queries from the client, retrieving data from the source, and sending it to the client. This also makes it possible for developers to create a system where multiple clients can simultaneously query GraphQL, which can retrieve the necessary data from the sources. With this type of setup, you will find that queries are much more efficient, especially at scale.

GraphQL is made up of a few components:

• Queries – requests made to the GraphQL layer.
• Resolvers – tells GraphQL how and where to fetch the data.
• Schema – describes the functionality that clients can use when connected to the GraphQL layer.

There are several open source projects that work with GraphQL, such as:

• Apolo is a server platform that you can use as a GraphQL layer in your system.
• Offix is ​​an offline client that allows mutations and queries to run even if a client is unreachable.
• Backward Graph is a command-line client that enables developers to generate GraphQL-enabled Node.js servers.
• OpenAPI for GraphQL is a command-line client and library that makes it possible to translate APIs described by the OpenAPI specifications into GraphQL.

Conclusion

If your application or service isn't deployed at scale or can easily work with a single database like MySQL, GraphQL isn't what you're looking for. However, if you know you will have applications that will rely on APIs to get data at scale, GraphQL could very well be the perfect language for your application or service.