Unix Timestamp vs. ISO 8601 for Storing Dates
A Unix timestamp is a compact number ideal for internal calculations, sorting, and comparisons, but isn't human-readable on its own; ISO 8601 (a standardized text format like 2027-04-20T14:30:00Z) is directly human-readable and unambiguous about timezone, making it generally preferable for data that people need to read directly, for logs, or for exchanging dates between different systems that might otherwise disagree on formatting conventions.
Both are widely used, standardized ways of representing the same underlying moment in time — the right choice depends mainly on who or what needs to read the value directly.
Where a raw timestamp is the better fit
For internal database storage, sorting large numbers of records by date, or performing date arithmetic in code, a Unix timestamp's simple numeric form is both compact and computationally efficient — no date-parsing logic is needed to compare two timestamps.
Where ISO 8601 is the better fit
For an API response, a log file a person might read directly, or any data exchanged between different systems or organizations, ISO 8601's readable, standardized, and unambiguous format (including explicit timezone information) avoids the misinterpretation risk that a bare, context-free number can carry.