Guides
Practical writing on Unix time, timestamps, and the bits of computer date-handling that catch developers out. Each piece is meant to be read in one sitting.
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What is Unix time? A complete guide
Unix time, POSIX time, epoch time — same thing, different names. A practical guide to what a Unix timestamp actually is, why it starts in 1970, and where it shows up in real software.
7 min read
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The Year 2038 Problem (Y2K38), explained
On 19 January 2038 at 03:14:07 UTC, every signed 32-bit Unix timestamp in the world overflows. Here is what actually happens, where it still matters, and how to find and fix it in your own code.
8 min read
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Seconds vs milliseconds vs microseconds: when each is right
A 10-digit number is probably seconds. A 13-digit number is probably milliseconds. But it depends on what you are doing — here is how to pick the right resolution and avoid the off-by-1000 bugs that come with mixing them up.
6 min read
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Unix timestamps in JavaScript: gotchas and patterns
JavaScript's native Date object is famously quirky. Here is a practical guide to working with Unix timestamps in JS — what to use, what to avoid, and the libraries worth reaching for.
8 min read
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Unix timestamps in Python: a practical guide
Python has three different time APIs and they all do slightly different things. Here is when to use time.time, when to use datetime, when to use Arrow or Pendulum, and the pitfalls in between.
8 min read
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Unix timestamps in SQL: Postgres, MySQL, and SQLite
Each SQL dialect handles Unix time slightly differently. Here is the practical reference for converting, storing, and indexing Unix timestamps in the three databases you are most likely to be running.
7 min read
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Timezones, UTC, and Unix time: common mistakes
Unix time is timezone-agnostic on the wire — but the moment a human sees it, a timezone has to enter the picture. Here are the timezone mistakes that bite developers most often, and how to keep your code out of them.
8 min read
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ISO 8601 vs Unix timestamps: when to use which
Two ways to represent a moment in time, both correct, both with strong opinions in the developer community. Here is when each is the better choice — and the cases where the answer is honestly just preference.
6 min read