> For the complete documentation index, see [llms.txt](https://support.portsip.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.portsip.com/development-portsip/rest-apis/version-22.3/get-started/timezones.md).

# Timezones

Some requests that create new data allow you to provide time zone information when specifying or generating timestamps. We use RFC 3339 timestamps to determine time zone information for API calls.