Unix Timestamp & Timezone: Complete Guide for Web Systems

Time is deceptively complex in software. Between Unix timestamps, UTC offsets, Daylight Saving Time (DST), and locale formatting, many systems ship with subtle bugs. This guide explains core concepts and practical workflows to make your applications time-robust.

Core Concepts

• Unix timestamp: seconds or milliseconds since 1970-01-01T00:00:00Z
• UTC vs local time: store in UTC, display in user locale
• DST: seasonal offset changes that affect local time

Best Practices

• Persist UTC; convert at the edge
• Normalize units: define seconds vs milliseconds across APIs
• Include timezone awareness in scheduling

Frontend & Backend

Use strict parsing and explicit time zones, avoid implicit conversions, and test edge cases (DST transitions, leap seconds).

Tools

Try the Unix Timestamp Converter to convert between timestamps and human-readable dates across time zones.