Scalars

Scalars are “leaf” values in GraphQL. There are several built-in scalars, and you can define custom scalars, too. (Enums are also leaf values.) The built-in scalars are:

• String, like a JSON or Ruby string
• Int, like a JSON or Ruby integer
• Float, like a JSON or Ruby floating point decimal
• Boolean, like a JSON or Ruby boolean (true or false)
• ID, which a specialized String for representing unique object identifiers
• ISO8601DateTime, an ISO 8601-encoded datetime
• ISO8601Date, an ISO 8601-encoded date
• JSON, This returns arbitrary JSON (Ruby hashes, arrays, strings, integers, floats, booleans and nils). Take care: by using this type, you completely lose all GraphQL type safety. Consider building object types for your data instead.
• BigInt, a numeric value which may exceed the size of a 32-bit integer

Learn more from the following links:

• Get started with Scalars in GraphQL