Flutter Dio post an object with array
It all depends on how the API expects it. I would suggest trying to encode it as JSON.
var params = { "item": "itemx", "options": jsonEncode([1,2,3]),};But sending complex data in query parameters isn't always that easy. Since you are using POST anyway, maybe send a JSON object as body instead of using query parameters.
var params = { "item": "itemx", "options": [1,2,3],}; ...Response response = await _dio.post(getAddToCartURL, options: Options(headers: { HttpHeaders.contentTypeHeader: "application/json", }), data: jsonEncode(params),);