Time & Date Guides
4 articlesTime and date handling is one of the most deceptively complex areas in software development. Time zones, daylight saving transitions, leap seconds, calendar systems, and locale-specific formatting create a minefield of edge cases that break applications in subtle ways — often only manifesting at specific times of year or for users in specific regions. These guides provide the foundational knowledge needed to handle time correctly: understanding UTC vs local time, choosing between Unix timestamps and ISO 8601 strings, parsing cron expressions for scheduled jobs, and calculating business days across different locales. You will learn the common pitfalls (storing local time instead of UTC, ignoring DST transitions, using string comparison for date ordering) and the battle-tested patterns that prevent them.
What You'll Learn
- Timezone handling: UTC, offsets, IANA timezone database, and DST edge cases
- Date formatting: ISO 8601, Unix timestamps, and locale-aware display formatting
- Cron expressions: syntax, scheduling patterns, and monitoring scheduled jobs
- Business day calculations: holidays, weekends, and locale-specific working calendars
- Age and duration calculations: handling leap years, month boundaries, and precision
- JavaScript Date API vs Temporal API: migration path and best practices
Why This Matters
Time bugs are among the most expensive to fix because they often go undetected until they cause real business impact — incorrect billing cycles, missed scheduled tasks, or compliance violations in time-sensitive industries like finance and healthcare. Getting time right from the start saves months of debugging and prevents costly production incidents.
All Articles
Time & Date in Programming: The Complete Developer Guide
A developer's guide to handling time: the Unix epoch, the Year 2038 overflow, IANA timezones and DST, ISO 8601, UTC storage, and scheduling with cron.
Cron Expression Guide: Syntax, Examples, and Common Patterns
Master cron syntax with clear examples. Learn standard 5-field and 6-field formats, special characters, DST anomalies, and platform differences for Linux, AWS, and Kubernetes.
Timezone Handling for Developers: UTC, DST, and Common Bugs
A comprehensive developer guide to timezone architecture. Master UTC, Daylight Saving Time (DST) anomalies, ISO 8601, and database timezone handling in PostgreSQL and MySQL.
Date Formatting for Developers: ISO 8601, Intl API, and Cross-Language Patterns
A practical guide to formatting dates and times in JavaScript, Python, and SQL. Covers ISO 8601 strictness, the Intl.DateTimeFormat API, timezone complexities, locale-aware formatting, and common bugs.