Overview

Unix Time & Timestamps Course

Learn Unix epoch time, seconds vs milliseconds, UTC, timezones, ISO 8601, and how to debug timestamps in logs and APIs.

This course teaches time as a data subject—how Unix timestamps represent instants, why seconds and milliseconds both exist, and how UTC, timezones, and ISO 8601 strings relate. It is not a button-by-button guide to any converter UI.

Who this course is for

  • Developers reading integer timestamps in logs, JSON, or SQL exports
  • Backend and mobile engineers integrating APIs that return created_at as epoch or ISO strings
  • Anyone who has been burned by off-by-1000 errors or “why is this date in 1970?”

What you will learn

  1. What Unix time measures and where epoch integers appear
  2. When systems use seconds vs milliseconds
  3. UTC, local wall time, IANA timezones, and daylight saving
  4. ISO 8601 and common log timestamp formats
  5. Pitfalls: Y2038, wrong units, ambiguous parsing
  6. Debugging timestamps across APIs, databases, and distributed logs

How to use this course

Follow the table of contents in order—the early lessons define vocabulary the later ones reuse. After each lesson you may experiment with a timestamp converter, but the goal is understanding the model, not memorizing tool steps.

Start lesson 1