Unix Timestamps Explained: What Every Developer Should Know

You're tailing a log file and you see this: [1712700000] ERROR: connection timeout What is 1712700000 ? Is it a bug? A timestamp? A version number? If you've ever stared at a number like that and felt unsure, this article is for you. By the end you'll know exactly what Unix timestamps are, why every serious API uses them, and how to convert them instantly without memorising any formula. What Is a Unix Timestamp? A Unix timestamp (also called an epoch timestamp) is simply the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC — a moment arbitrarily chosen as the starting point of computer time, known as the Unix epoch. That's it. No timezones, no daylight saving adjustments, no locale quirks. Just a single integer that means the same thing on every machine on the planet. 1712700000 translates to April 9, 2024, 20:00:00 UTC . Why 1970? The Unix operating system was developed in the early 1970s. The designers needed a fixed reference point that was recent enough to ke