iCalendar (.ics) Generator API

Create .ics calendar files for Google, Apple and Outlook: events, all-day events, recurrence, reminders, and yearly events on a lunar date (giỗ, rằm) expanded to solar dates.

POSTGEThttps://apibox.io.vn/v1/ics

Developer utilities▶ Try it online

The ICS API builds iCalendar files (RFC 5545) that every calendar app imports: Google Calendar, Apple Calendar, Outlook, Thunderbird. Send one event as parameters or many as a JSON events array, each with a title, start (YYYY-MM-DDTHH:MM in Vietnam time, or a date for all-day events), end or duration_minutes, location, description, URL, recurrence rule (rrule, e.g. FREQ=WEEKLY;COUNT=10) and reminders (alarm_minutes). Text is escaped and long lines folded as the standard requires, and a VTIMEZONE for Asia/Ho_Chi_Minh is included.

Standard calendars cannot repeat an event on a lunar date. With lunar: { day: 10, month: 3, years: 10 } the API computes the solar date of that lunar date for each year (10/3 âm lịch → 26/4/2026, 16/4/2027…) and writes one event per year: death anniversaries (giỗ), rằm and mùng 1, lunar birthdays, Hung Kings Day. A day 30 in a 29-day month falls on the last day of the month.

The response is a downloadable .ics file; format=json returns the file content and the list of computed dates instead.

Parameters

Name	In	Type	Required	Default
`events`	body	array	no		Events: {title, start, end, duration_minutes, all_day, location, description, url, rrule, alarm_minutes, lunar}.
`title`	body\|query	string	no		Single event: title (with `start` or `lunar`).
`start`	body\|query	string	no		`YYYY-MM-DD` or `YYYY-MM-DDTHH:MM` (Vietnam time).
`lunar`	query	string	no		Single event on a lunar date `DD/MM`, with `years` and `from_year`.
`name`	body\|query	string	no		Calendar name.
`format`	body\|query	string	no	`ics`	`ics` (file) or `json`.

Example

curl -X POST "https://apibox.io.vn/v1/ics" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name":"Lịch gia đình","format":"json","events":[{"title":"Giỗ ông nội","lunar":{"day":10,"month":3,"years":3,"from_year":2026},"all_day":true,"alarm_minutes":1440}]}'

const res = await fetch('https://apibox.io.vn/v1/ics', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "name": "Lịch gia đình",
    "format": "json",
    "events": [
      {
        "title": "Giỗ ông nội",
        "lunar": {
          "day": 10,
          "month": 3,
          "years": 3,
          "from_year": 2026
        },
        "all_day": true,
        "alarm_minutes": 1440
      }
    ]
  }),
});
const data = await res.json();
console.log(data);

import requests

res = requests.post(
    "https://apibox.io.vn/v1/ics",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    json={"name": "Lịch gia đình", "format": "json", "events": [{"title": "Giỗ ông nội", "lunar": {"day": 10, "month": 3, "years": 3, "from_year": 2026}, "all_day": True, "alarm_minutes": 1440}]},
    timeout=30,
)
print(res.json())

<?php
$ch = curl_init('https://apibox.io.vn/v1/ics');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_HTTPHEADER => ['Authorization: Bearer YOUR_API_KEY', 'Content-Type: application/json'],
    CURLOPT_POSTFIELDS => '{"name":"Lịch gia đình","format":"json","events":[{"title":"Giỗ ông nội","lunar":{"day":10,"month":3,"years":3,"from_year":2026},"all_day":true,"alarm_minutes":1440}]}',
]);
$response = curl_exec($ch);
print_r(json_decode($response, true));

Response

{
  "events": 3,
  "occurrences": [
    {
      "title": "Giỗ ông nội",
      "date": "2026-04-26"
    },
    {
      "title": "Giỗ ông nội",
      "date": "2027-04-16"
    },
    {
      "title": "Giỗ ông nội",
      "date": "2028-04-04"
    }
  ],
  "ics": "BEGIN:VCALENDAR\r\nVERSION:2.0\r\nPRODID:-//APIBox//ics//VI\r\n…"
}

Use cases

“Add to calendar” buttons for bookings, webinars and events
Family calendars of death anniversaries and rằm on lunar dates
Export schedules from HR, school and booking systems
Recurring reminders for subscriptions and deadlines

FAQ

How do I repeat an event every lunar year?

Use lunar: { day, month, years, from_year }. Calendar apps have no lunar recurrence, so the API writes one event per year with the right solar date.

Which time zone is used?

Times are Vietnam time (Asia/Ho_Chi_Minh, UTC+7); the file includes the time zone definition so apps abroad show the right local time.

Can I add reminders?

Yes, alarm_minutes (a number or an array of up to 5) adds display alarms before the event.

iCalendar (.ics) Generator API

Parameters

Example

Response

Use cases

FAQ

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