---
title: Custom Data Types (2019/03)
slug: develop/custom-data-types-201903
docTags: 
createdAt: 2025-11-14T22:42:43.623Z
---

The data types below, which are consistent across all APIs, are used in the BSN.cloud Main API as are the entities in the child pages beneath this page.

## DateTime

Defines a moment in time using a sortable UTC pattern value format, based on [rfc3339](https://datatracker.ietf.org/doc/html/rfc3339). An example would be 2022-02-18T16:57:00.123Z 

## DayOfWeek

Represents the day of the week from Sunday to Saturday. The days are specified as a string list (for example, "Monday, Wednesday, Friday").  

## Nullable\<int>

Data types that are prefixed with "nullable" (for example, nullable\<int>) accept null value. Most data types are not nullable in this API framework, so this data type allows you to accept null for a non-nullable type. By default, nullable types are strings, objects, and arrays.

## TimeSpan

Represents a period of time. Possible values are: 

- 00:00 - 23:59 (hours and minutes)
- 00:00:00 - 23:59:59 (hours, minutes, and seconds. This is the default format)
- 00:00:00.000 - 23:59:59.999 (hours, minutes, seconds, and milliseconds)
- 1.00:00:00 - 99999.23:59:59 (date, hours, minutes, seconds)
- 1.00:00:00.000 - 99999.23:59:59.999 (date, hours, minutes, seconds, and milliseconds)

## Uri

A representation of a resource available on the internet or intranet. This data type is nullable.