# API formats and time zones | Orion Data API v1.3

> For the complete documentation index, see [llms.txt](https://docs.oriondata.io/llms.txt)

Date formats, nullable types, and other conventions used throughout the Orion Data API.

The Orion Data API follows a small set of conventions consistently across every endpoint.

## Date and time formats

| Type     | Format                | Example               |
| -------- | --------------------- | --------------------- |
| Date     | `yyyy-MM-dd`          | `2024-09-09`          |
| DateTime | `yyyy-MM-ddTHH:mm:ss` | `2025-05-19T00:00:00` |

Where an endpoint accepts a DateTime, the time portion is optional. Supplying a date-only value is equivalent to midnight on that date.

## Time zones

Sensor reading timestamps are returned in the Device’s local standard time. Devices do not observe daylight saving.

The `lastUpload` field on a Device is the exception: it is returned in UTC.

## Nullable types

Field descriptions that end with a `?` indicate that the field is nullable. For example, `String?` may be either a string or `null`.

## Authentication

Endpoints listed as requiring authorisation must be called with a valid JWT bearer token in the `Authorization` header. See [Authenticate API requests](https://docs.oriondata.io/api/orion-data/v1-3/guides/authentication/).

## Sample data

All sample requests and responses in this documentation use generated values. They do not represent real Devices, sensors, or readings.