Well, I prefer not to put a "\n" in dates but you do you mate

All other formats are inferior

int time = 1686650138000;

As someone that works a lot with high-frequency sensor data, we need the microseconds too!! Use this one: %Y-%m-%d_%H:%M:%S.%f

In ISO8601 I trust.

POSIX time or bust!

This is the way.

ISO 8601

I accidentally the timezone.

Unix timestamp on top

The only and best way