api-generator-templates/Swift/blocks/class/coding-keys.twig

    {% if fields is not empty %}
    private enum CodingKeys: String, CodingKey {
        {% for field in fields %}
        case {{ field.name }}{% if field.name != field.jsonName %} = "{{- field.jsonName -}}"{% endif %}
        {%- endfor %}
    }
    {% endif %}