ID

The ID scalar type represents a unique identifier, often used to refetch an object or as the key for a cache. The ID type is serialized in the same way as aString; however, it is not intended to be human‐readable. While it is often numeric, it should always serialize as aString.

Result Coercion

GraphQL is agnostic to ID format, and serializes to string to ensure consistency across many formats ID could represent, from small auto‐increment numbers, to large 128‐bit random numbers, to base64 encoded values, or string values of a format likeGUID.

GraphQL servers should coerce as appropriate given the ID formats they expect. When coercion is not possible they must raise a field error.

Input Coercion

When expected as an input type, any string (such as"4") or integer (such as4) input value should be coerced to ID as appropriate for the ID formats a given GraphQL server expects. Any other input value, including float input values (such as4.0), must raise a query error indicating an incorrect type.