[CRMEntity("account")]
public class AccountModel 
{
    [CRM(FieldName = "accountid")]
    public Guid? AccountId { get; set; }

    [CRM(FieldName = "name")]
    public string AccountName { get; set; }

    [CRM(FieldName = "accountnumber")]
    public string AccountNumber { get; set; }

    [CRM(FieldName = "createdon")]
    public DateTime? CreatedOn { get; set; }

    [CRM(FieldName = "creditlimit")]
    public Decimal? CreditLimit { get; set; }

    // this field will have a custom map
    [CRM(FieldName = "customertypecode", CustomFieldMap = typeof(CustomerTypeCodeType?))]
    public CustomerTypeCodeType? CustomerTypeCode { get; set; }

    [CRM(FieldName = "donotemail")]
    public bool? DoNotEmail { get; set; }

    [CRM(FieldName = "entityimage")]
    public Decimal? EntityImage { get; set; }

    [CRM(FieldName = "modifiedon")]
    public DateTime? ModifiedOn { get; set; }

    [CRM(FieldName = "opendeals")]
    public int? OpenDeals { get; set; }

    [CRM(FieldName = "owninguser")]
    public string OwningUserName { get; set; }

    [CRM(FieldName = "owninguser")]
    public Guid? OwningUserId { get; set; }

    [CRM(FieldName = "ownerid")]
    public Guid? OwnerId { get; set; }

    [CRM(FieldName = "status")]
    public int? Status { get; set; }

    [CRM(FieldName = "websiteurl")]
    public string Website { get; set; }
        
    // address
    [CRM(FieldName = "address1_name")]
    public string Address1Name { get; set; }

    [CRM(FieldName = "address1_id")]
    public Guid? Address1LineId { get; set; }

    [CRM(FieldName = "address1_line1")]
    public string Address1Line1 { get; set; }

    [CRM(FieldName = "address1_city")]
    public string Address1City { get; set; }

    [CRM(FieldName = "address1_state")]
    public string Address1State { get; set; }

    [CRM(FieldName = "address1_postalcode")]
    public string Address1PostalCode { get; set; }

    [CRM(FieldName = "address1_country")]
    public string Address1Country { get; set; }

    [CRM(FieldName = "address1_composite")]
    public string Address1Composite { get; set; }

    [CRM(FieldName = "address1_longitude")]
    public string Address1Longitude { get; set; }
} 

public enum CustomerTypeCodeType {
    Competitor = 1,
    Consultant = 2,
    Customer = 3,
    Investor = 4,
    Partner = 5,
    Influencer = 6,
    Press = 7,
    Prospect = 8,
    Reseller = 9,
    Supplier = 10,
    Vendor = 11,
    Other = 12
}

public class CustomAutoMapsHelper {
    public static void CustomMapping<T>(T model, Type customFieldMap, PropertyInfo property, object value) where T : class {
        if (customFieldMap == typeof(CustomerTypeCodeType?)) {
            // CustomerTypeCodeType?
            OptionSetValue optSet = ((JObject)value).ToObject<OptionSetValue>();
            property.SetValue(model, (CustomerTypeCodeType)optSet.Value);
        }
    }
}

// POST api/values
[HttpPost]
public void Post([FromBody] JObject data) {            
    JObject postImage = (JObject)data["PostEntityImages"][0]["value"];

    // instantiate model
    AccountModel model = new AccountModel();

    // map JObject data to model
    DynamicsCrmMappingUtility<AccountModel>.CustomMappingMethod = CustomAutoMapsHelper.CustomMapping;
    DynamicsCrmMappingUtility<AccountModel>.MapToModel(postImage, model);

    string accountName = model.AccountName;
    string accountNumber = model.AccountNumber;
}