What is a unix timestamp?
A unix timestamp counts non-leap seconds since 1 January 1970 00:00:00 UTC — the unix epoch. Databases, APIs, and log files store dates this way because integers sort and compare cleanly. When you convert unix time to date, you translate that integer back into a calendar clock humans can read.
The same value may appear as a unix stamp, epoch unix timestamp, or POSIX timestamp depending on documentation. This online timestamp converter treats them identically and shows local time, UTC, and ISO output side by side.