schema.json

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "$ref": "#/definitions/RootNamespace.SubNamespace.HelperA",
    "definitions": {
        "RootNamespace.Def": {
            "properties": {
                "nest": {
                    "$ref": "#/definitions/RootNamespace.Def"
                },
                "prev": {
                    "$ref": "#/definitions/RootNamespace.Def"
                },
                "propA": {
                    "$ref": "#/definitions/RootNamespace.SubNamespace.HelperA"
                },
                "propB": {
                    "$ref": "#/definitions/RootNamespace.SubNamespace.HelperB"
                }
            },
            "required": [
                "nest",
                "prev",
                "propA",
                "propB"
            ],
            "type": "object"
        },
        "RootNamespace.SubNamespace.HelperA": {
            "properties": {
                "propA": {
                    "type": "number"
                },
                "propB": {
                    "$ref": "#/definitions/RootNamespace.SubNamespace.HelperB"
                }
            },
            "required": [
                "propA",
                "propB"
            ],
            "type": "object"
        },
        "RootNamespace.SubNamespace.HelperB": {
            "properties": {
                "propA": {
                    "$ref": "#/definitions/RootNamespace.SubNamespace.HelperA"
                },
                "propB": {
                    "$ref": "#/definitions/RootNamespace.Def"
                }
            },
            "required": [
                "propA",
                "propB"
            ],
            "type": "object"
        }
    }
}