GraphQL<\/a> is an open-source data query and manipulation language for APIs<\/a>, and a runtime for fulfilling those queries with existing data. It was developed internally by Facebook<\/a> in 2012 before being publicly released in 2015. It provides a more efficient and powerful alternative to the REST<\/a> architectural style by allowing clients to define the exact structure of the data they need. According to the official GraphQL documentation<\/a>, this prevents problems such as over-fetching and under-fetching of data.<\/p> The primary component of a GraphQL<\/a> implementation is the Schema<\/a>, which uses a strong type system to describe the data available on the server. Clients interact with the service using three main operation types: Queries<\/a> for reading data, Mutations<\/a> for writing or modifying data, and Subscriptions<\/a> for real-time updates. This flexibility makes it highly popular in modern Web-Development<\/a> and Mobile-Development<\/a>. Developers often use tools like Apollo Client<\/a> or Relay<\/a> to integrate these services into applications. For a deeper technical overview, the Wikipedia entry on GraphQL<\/a> provides extensive history and context.<\/p>Core Principles and Features<\/h2>