GraphQL type reference

Scalar types in GraphQL represent primitive leaf values in a GraphQL schema. These are the most basic data types that resolve to a single value. Unlike object types, scalar types cannot have sub-fields. GraphQL comes with a set of default scalar types:

These scalar types serve as the building blocks for more complex types in your schema. They are used to define fields that contain simple, singular values. In addition to these built-in scalars, AWS AppSync provides you with additional scalars for different use cases.

Interfaces and Unions in GraphQL are abstract types that allow for flexible and extensible schema design. They provide mechanisms for grouping related types and enabling polymorphic queries. An Interface in GraphQL is an abstract type that defines a set of fields that a type must include to implement the interface. It serves as a contract for objects by specifying a common set of fields that implementing types must have. Interfaces are useful when you want to return an object or field that can be of several different types, but still have some guaranteed fields. By contrast, a Union in GraphQL represents a type that could be one of several object types, but does not define any common fields between those types. Unions are helpful when you need to return a field that can be of multiple types, and these types don't necessarily share common fields. Both Interfaces and Unions are particularly useful in scenarios where a field might return different types of data, enabling clients to query for specific fields based on the returned type.

This section is used as a reference for schema types.

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