The 10 most crucial GraphQL interview questions and answers for 2023

While this may seem like a fundamental GraphQL interview question, you can make the answer interesting by adding your personal experience with the language.

GraphQL is a query language invented by Facebook in 2012 that offers a standard interface for data retrieval and modification between the client and the server. The client uses queries to request data from the GraphQL server. Client-specified inquiries are those in which the answer format is described in the query and determined by the client rather than the server.

As opposed to standard REST APIs, the data structure is not hardcoded, making data retrieval from the server more efficient for the client.

GraphQL is frequently misunderstood as database technology; however, this is a widespread misunderstanding. GraphQL is an API query language. In that respect, it's database agnostic, meaning it can work with any database or perhaps none at all.

When users use GraphQL to request data, it merely retrieves the least amount of data necessary by the client. Even if the object model has a large number of fields, the client can only request the required fields.

These types of GraphQL interview questions explicitly seek your working experience with the language. Dig into all your experience and share the best examples.

Where your customer requires a flexible answer style to prevent multiple queries and extensive data transformation with the burden of keeping them in sync, GraphQL comes in handy.

Using a GraphQL server, a client-side developer may easily alter the return format without affecting the backend.

You may describe the essential data more naturally with GraphQL. It can speed up development since the needed data is more comparable to your component structure in application architectures like top-down rendering in React.

GraphQL has some key concepts. They are:

• Hierarchical
• Product-centric
• Strong-typing
• Client-specific queries
• Introspective

The three sorts of operations supported by GraphQL are query, mutation, and subscription. The request is made using the query, which is a read action; mutation is used for write operations, and subscription is used to listen for any data changes. If the client is subscribed to that event, the server sends a notification message to the client whenever data changes.

The most significant distinction between REST and GraphQL is that GraphQL does not deal with specific resources. Everything, in GraphQL, is viewed as a graph, which is linked and may be searched to meet the demands of the app.

This is an example of a GraphQL interview question that assesses your detail orientation.

The difficulty of maintaining server-side caching is still an area of concern with GraphQL, especially when compared to REST. It's simple to cache data for each endpoint with REST because the data format is guaranteed not to change.

With GraphQL, on the other hand, it's impossible to predict what a client will want next; thus, a cache layer sitting behind the API makes little sense. Therefore, server-side caching in GraphQL remains a hurdle.

A query to be processed by a GraphQL server usually comes in as a single String. Therefore, this string must be tokenized (divided into meaningful substrings) and processed into a machine-readable form. An abstract syntax tree, or AST, is the name for this form.

When GraphQL processes a query, it walks through the tree, executing each component against the schema. Every compiler, from C++ to Chrome's JavaScript VM to Babel, starts by converting raw strings to an AST.

When the query in GraphQL is huge and contains reusable components, the fragment is utilized. You may utilize the reusable portion to construct a fragment, which you can then use in the query. The notion of the fragment was created to make it easy to organize code and reduce duplication.

No, input types are not allowed to implement inheritance. In addition, the GraphQL type system does not support inheritance (the extends keyword adds fields to an existing type, not inheritance).