How to Parse Nested JSON ln Flutter?

You can use app.quicktype.io or any other online sites for parsing your model so fast. Otherwise you need to write manually.

// To parse this JSON data, do
//
//     final data = dataFromJson(jsonString);

import 'dart:convert';

Data dataFromJson(String str) => Data.fromJson(json.decode(str));

String dataToJson(Data data) => json.encode(data.toJson());

class Data {
    Data({
        this.data,
        this.message,
        this.status,
    });

    DataClass data;
    String message;
    int status;

    factory Data.fromJson(Map<String, dynamic> json) => Data(
        data: DataClass.fromJson(json["data"]),
        message: json["message"],
        status: json["status"],
    );

    Map<String, dynamic> toJson() => {
        "data": data.toJson(),
        "message": message,
        "status": status,
    };
}

class DataClass {
    DataClass({
        this.address,
        this.cityId,
        this.cityName,
        this.companyName,
        this.creditDays,
        this.cusotmerId,
        this.email,
        this.gstNo,
        this.isApproved,
        this.lat,
        this.long,
        this.mobile,
        this.pincode,
        this.route,
        this.stateId,
        this.stateName,
        this.uniqueNumber,
    });

    String address;
    String cityId;
    String cityName;
    String companyName;
    String creditDays;
    String cusotmerId;
    String email;
    String gstNo;
    String isApproved;
    String lat;
    String long;
    String mobile;
    String pincode;
    String route;
    String stateId;
    String stateName;
    String uniqueNumber;

    factory DataClass.fromJson(Map<String, dynamic> json) => DataClass(
        address: json["Address"],
        cityId: json["CityID"],
        cityName: json["CityName"],
        companyName: json["CompanyName"],
        creditDays: json["CreditDays"],
        cusotmerId: json["CusotmerID"],
        email: json["Email"],
        gstNo: json["GSTNo"],
        isApproved: json["IsApproved"],
        lat: json["Lat"],
        long: json["Long"],
        mobile: json["Mobile"],
        pincode: json["Pincode"],
        route: json["Route"],
        stateId: json["StateID"],
        stateName: json["StateName"],
        uniqueNumber: json["UniqueNumber"],
    );

    Map<String, dynamic> toJson() => {
        "Address": address,
        "CityID": cityId,
        "CityName": cityName,
        "CompanyName": companyName,
        "CreditDays": creditDays,
        "CusotmerID": cusotmerId,
        "Email": email,
        "GSTNo": gstNo,
        "IsApproved": isApproved,
        "Lat": lat,
        "Long": long,
        "Mobile": mobile,
        "Pincode": pincode,
        "Route": route,
        "StateID": stateId,
        "StateName": stateName,
        "UniqueNumber": uniqueNumber,
    };
}