# Overview

- [Query types](/graphql/overview/query-types.md): Overview of available query and field naming concepts representing how the data is provided.
- [Stream queries](/graphql/overview/query-types/stream-queries.md): List of factors resulting in resource cursor update
- [Error codes](/graphql/overview/error-codes.md): The list of possible error codes to occur in course of executing API mutations.
- [Schema](/graphql/overview/schema.md)
- [Queries](/graphql/overview/schema/queries.md): Queries allow retrieving data from the server.
- [Mutations](/graphql/overview/schema/mutations.md): Mutations allow modifing data on the server.
- [Objects](/graphql/overview/schema/objects.md): Objects represent the resources you can access.
- [Interfaces](/graphql/overview/schema/interfaces.md): Interfaces represent a parent for Objects providing definition of common fields.
- [Scalars](/graphql/overview/schema/scalars.md): Scalars represent primitive values like Integer or String.
- [Input objects](/graphql/overview/schema/input-objects.md): Input objects represent a set of fields allowing describing mutation.
- [Enums](/graphql/overview/schema/enums.md): Enums represent a predefined sets o values.
- [Unions](/graphql/overview/schema/unions.md): Unions represent possible many types.