Date handling is notoriously difficult in programming. If you have ever had a user complain that their appointment was booked for 3 AM instead of 3 PM, you know the pain of time zones.
The Golden Rule
To avoid chaos, modern web applications follow one simple rule: Store in UTC, Display in Local.
- Backend: Your database should always store timestamps in UTC (Universal Coordinated Time) or as raw Unix integers. Never store time as "EST" or "+05:00".
- Frontend: The user's browser knows their time zone. You send the UTC time to the browser, and JavaScript converts it to the user's local time just before displaying it.
ISO 8601 vs. Unix Timestamp
While Unix timestamps are efficient for storage, APIs often use the ISO 8601 format (e.g., 2025-11-25T14:30:00Z) because it is human-readable.
Our converter handles both. It bridges the gap between the efficient integers your database uses and the readable ISO strings your API consumers expect.
Testing Your App
When testing your application, it is vital to verify that your conversions are correct. Generating a timestamp for "now" and seeing if it matches your local clock is the quickest sanity check.
Verify Your Conversions
Check if your UTC storage matches your local display time.
Conclusion
Time zones don't have to be scary. By standardizing on UTC and using reliable tools to check your work, you can build applications that work perfectly from London to Tokyo.