Now a day’s most of the web or mobile applications fetch data from server which is stored in a database. REST API provides an interface to stored data that require by the applications. GraphQL is a query language for REST API's not for server databases. It is database agnostic and effectively can be used in any context where an API is used. GraphQL provide platform for declarative data fetching where client need to specify what data needs from API in response. Instead of multiple endpoints that return fixed data structures, a GraphQL server only exposes a single endpoint and responds with precisely the data a client asked for. GraphQL minimizes the amount of data that needs to be transferred over the network and improves applications operating under these conditions. Introduction to GraphQL API on Ruby on Rails Start with adding gem in Gemfile gem ‘graphql’ Run command bundle install Run command rails generate graphql:install Above command will add gr...