Timezone API: Handle Global Time Zones Without Moment.js

#api #javascript #tutorial #webdev

Moment.js is 67KB. Luxon is better but still a dependency. For timezone conversion in a global app, you might not need either — here's how an API solves it without client-side code.

The Problem with Client-Side Timezone Handling

// This is wrong in multiple ways:
const d = new Date(timestamp);
d.toLocaleString('ko-KR', { timeZone: 'Asia/Seoul' });
// - Browser behavior varies
// - DST transitions handled inconsistently
// - "Asia/Seoul" availability depends on OS

Server-Side via API (Reliable)

import requests
from datetime import datetime

def convert_timezone(timestamp: str, from_tz: str, to_tz: str) -> dict:
    resp = requests.get("https://api.lazy-mac.com/timezone/convert", params={
        "datetime": timestamp,
        "from_timezone": from_tz,
        "to_timezone": to_tz
    })
    return resp.json()

result = convert_timezone("2026-04-11T09:00:00", "America/New_York", "Asia/Seoul")
# {
#   "original": "2026-04-11T09:00:00",
#   "converted": "2026-04-11T22:00:00",
#   "from_tz": "America/New_York",
#   "to_tz": "Asia/Seoul",
#   "offset_diff": "+13:00",
#   "dst_active_from": false,
#   "dst_active_to": false
# }

Meeting Scheduler Pattern

def find_meeting_time(participants: list[dict]) -> list:
    """
    participants = [
        {"name": "Alice", "timezone": "America/New_York", "working_hours": [9, 17]},
        {"name": "Bob", "timezone": "Asia/Seoul", "working_hours": [9, 18]},
    ]
    """
    resp = requests.post("https://api.lazy-mac.com/timezone/find-overlap", json={
        "participants": participants,
        "duration_minutes": 60,
        "date": "2026-04-15"
    })
    return resp.json()['available_slots']

List All Timezones

resp = requests.get("https://api.lazy-mac.com/timezone/list", params={
    "region": "Asia",
    "include_offset": True,
    "current_time": True
})
# Returns all Asia/* timezones with current local time