Where in JSON Schema can you specify required? What are the options?

In JSON Schema, the keyword required is used to specify mandatory properties of an object. It is applied within the object description (type object) and is an array of strings with the names of required fields.

Example:

{
  "type": "object",
  "properties": {
    "name": { "type": "string" },
    "age": { "type": "integer" }
  },
  "required": ["name"]
}

In this example, the name field is mandatory, while age is not.

In JSON Schema, there are no other ways to specify required fields except through the required key inside the object. For nested objects, required should be specified separately within their schema.