How to define a JSON schema that requires at least one of many properties

Question

I would like to know if I can define a JSON schema (draft 4) that requires at least one of many properties possible for an object. I already know of allOf,

Answer 1

You may use minProperties: number (and maxProperties: number if needed). That would shorten the schema definition:

{
     type: "object",
     minProperties: 1,
     properties: [/* your actual properties definitions */],
}

Link to documentation: https://json-schema.org/understanding-json-schema/reference/object.html#size

Answer 2

To require at least one of a set of properties, use required inside a series of anyOf options:

{
    "type": "object",
    "anyOf": [
        {"required": ["id"]},
        {"required": ["email"]}
        // any other properties, in a similar way
    ],
    "properties": {
        // Your actual property definitions here
    }
{

If any of the properties you want is present ("id", "email"), then it will pass the corresponding option in allOf.