Zero to Production with Fullstack GraphQL and React with Hasura team

GraphQL is a query language for APIs and a runtime for executing those queries by using a type system you define for your data. It is important because it allows clients to request exactly the data they need, making it possible to get all required data in a single request, which can improve the efficiency of data retrieval and reduce bandwidth usage.

Unlike REST APIs that require loading from multiple URLs, GraphQL APIs get all the data your app needs in a single request. Users can specify exactly what data they need, which often avoids over-fetching or under-fetching data, unlike REST APIs.

The main benefits of using GraphQL include improved data retrieval efficiency, reduced number of API requests, flexible data querying capabilities, and better performance in handling complex systems with multiple and diverse data objects.

A GraphQL schema is a blueprint of the query language's data types and defines how clients can access the data points. It is the basis of the API's structure, specifying the types of data that can be queried and the relationships among those types.

In GraphQL, 'queries' are used to fetch data and 'mutations' are used to modify data. Queries can retrieve the data according to the specified schema, while mutations change server-side data, like updating, deleting, or creating new records.

GraphQL can enhance the developer experience by providing powerful development tools, reducing the amount of code developers need to write, offering introspection capabilities, and allowing for detailed error messages which help in debugging and development.

Resolvers in GraphQL are functions that handle the fetching of data for a specific field in a schema. They connect the GraphQL server with a data source, such as a database, and define the technique for fetching or modifying the data associated with that field.

Hestera is a tool used in GraphQL implementations that enhances performance by batching database queries, caching query results, and automating parts of the GraphQL API setup. It helps in managing data interactions more efficiently and supports extensions like remote schemas and event triggers.