What Is GraphQL?: GraphQL is a query language for your API and a server-side runtime for executing queries by using a schema type system you defined for your data. Graphql is not tied to any specific programming language(like NestJS, Java, .NET, etc) or database or storage engine. How GraphQL Different From Rest API: GraphQL exposes a single endpoint. HTTP-POST is the only Http verb recommended by GraphQL. Client applications(consumers of GraphQL API) can give instructions to GraphQL API about the response data. Schema vs Code First Approach: Schema First Approach - GraphQL SDL (Schema definition language) is a new syntax language, which is independent of any programming language and also integrates with any programming language. But while integrating with any programming language GraphQL Schema needs to be mapped with objects or classes or interface of the specific programming language to build communication between GraphQL Schema and programming language. In Nest