Unix timestamp → ISO 8601
ISO 8601 (and the closely related RFC 3339) strings such as 2023-11-14T22:13:20.000Z are the preferred format for APIs, JSON payloads, and structured logs. Paste an epoch and copy the ISO string in one click.
Always in UTC
The ISO output uses the Z (Zulu) suffix, meaning UTC. That keeps serialization unambiguous across regions and daylight-saving changes.