list<master> b = (list<master>)JSON.deserialize(req.requestBody.toString(),list<master>.class);

    system.debug('----------b----------'+b);

list<Account> accList = new list<Account>();
    Account acc = new Account();

    if(!b.isEmpty())
    {

        for(master mas: b)
        {
             Id regularShowId = Schema.SObjectType.Account.RecordTypeInfosByName.get('Person Account').RecordTypeId;

            if(!string.isBlank(mas.MagentoID))
            {
                acc.Magento_ID__c = string.valueof(mas.MagentoID);
            }
            if(!string.isBlank(mas.fname))
            {
                acc.firstname= string.valueof(mas.fname);
            }
            if(!string.isBlank(mas.lname))
            {
                acc.lastname= string.valueof(mas.lname);
            }
            if(!string.isBlank(mas.Phon))
            {
                acc.Phone= string.valueof(mas.Phon);
            }
            if(!string.isBlank(mas.DateCustomerAdded))
            {
                acc.Date_Customer_Added__c = date.valueof(mas.DateCustomerAdded);
            }
            if(!string.isBlank(mas.Email))
            {
                acc.Email__c= string.valueof(mas.Email);
            }


                //acc.Date_Customer_Added__c = datetime.valueof(mas.DateCustomerAdded);
                acc.RecordtypeID = 'regularShowId';

            accList.add(acc);
        }
            Database.UpsertResult[] upsertResult = Database.upsert(accList,Account.Email__c,false);

    }
    // return JSON.serialize(acc);
    return 'Success';

public master()
   {

   }