> ## Documentation Index
> Fetch the complete documentation index at: https://docs.caspen.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Dates and Times

> How Caspen handles dates, times, and timezone data

## UTC Requirement

<Warning>
  **All dates and times must be in UTC**. The API does not accept or return timezone-specific dates. Always convert local times to UTC before sending requests.
</Warning>

## Date Format Standards

### ISO 8601 Format

All dates and times use the ISO 8601 format with UTC timezone:

```
YYYY-MM-DDTHH:mm:ssZ
```

**Examples:**

* `2024-01-15T14:30:00Z` (2:30 PM UTC)
* `2024-01-15T00:00:00Z` (midnight UTC)

### Date-Only Format

For fields that expect a calendar date, send the date string directly:

```
YYYY-MM-DD
```

Example: `2024-01-15`