gistfile1.txt

'router' => [
        'routes' => [
            'ispaccount.rest.ispaccount' => [
                'type' => 'Segment',
                'options' => [
                    'route' => '/api/ispaccount[/:ispaccount_id]',
                     'constraints' => [
                         'ispaccount_id' => '[a-zA-Z][a-zA-Z0-9_-]+',
                     ],
                    'defaults' => [
                        'controller' => 'ispaccount\\V1\\Rest\\ISPAccount\\Controller',
                    ],
                ],
            ],
        ],
    ],