Scalars are primitive data types that represent leaf values in GraphQL. Built-in scalars include:

• String: UTF-8 character sequence
• Int: 32-bit signed integer
• Float: Double-precision floating-point
• Boolean: true or false
• ID: Unique identifier

You can also define custom scalars:

scalar Date
scalar Email
scalar URL

type User {
  id: ID!
  email: Email!
  birthDate: Date
}