# Dates and times Every time the API sends or accepts, such as when a website was created or last tested, is a **Unix timestamp**: whole seconds since 00:00:00 UTC on January 1, 1970. `0` means "never", as in a `lastTested` of `0` for a website that has not been tested yet. ```javascript const lastTested = new Date(website.lastTested * 1000); ``` ```python from datetime import datetime, timezone last_tested = datetime.fromtimestamp(website["lastTested"], tz=timezone.utc) ``` ```php $lastTested = (new DateTimeImmutable())->setTimestamp($website['lastTested']); ``` Results that cover days, such as a score's trend, read those days in the time zone you pass as `timezone`, an IANA name such as `Europe/London`. It defaults to `UTC`. See [Results](https://developers.silktide.com/v1/concepts/results.md). The one exception is an [Analytics](https://developers.silktide.com/v1/analytics.md) series, such as visitors over time. It writes the time each step starts as `YYYY-MM-DD HH:MM:SS`, in that `timezone`.