Listener # app/config/config.yml fos_rest: format_listener: enabled: true rules: - path: '^/' host: 'api.%domain%' priorities: ['json', 'xml'] fallback_format: json prefer_extension: false - path: '^/api' priorities: [ 'xml', 'json'] fallback_format: xml attributes: { _controller: FOS\RestBundle\Controller\ExceptionController } prefer_extension: false - path: '^/' priorities: [ 'text/html', '*/*'] fallback_format: html prefer_extension: true