AToCal — Add To Calendar

Vibe-coded: AToCal is written by Mistral AI's coding agent, not by hand. The maintainer sets the goals, makes the product decisions and tries the app out in the browser; there has been no independent human code review and no security audit.

A Nextcloud app that lets remote applications create events in the authenticated user's Nextcloud Calendar via a simple link.

How it works

remote app                  Nextcloud (atocal)
    |                              |
    |  GET /apps/atocal/confirm    |
    |  summary, start, end, ...    |
    |----------------------------->|
    |                              |  confirm page
    |<-----------------------------|
    |                              |
    |  POST /apps/atocal/create    |  (CSRF token from form)
    |----------------------------->|
    |                              |  event in "Personal" calendar
    |<-----------------------------|  redirect to Calendar app

The remote app links the user to the confirm page. The user reviews the event and submits the form. The event lands in a calendar the user chooses. The user adds invitees/attendees to the event, who receive an invitation, as long as the user owns the calendar. After the event is created the browser opens the Calendar app.

Routes

Method	Path	Purpose
GET	/apps/atocal/confirm	Show confirmation page
POST	/apps/atocal/create	Create the event
GET	/apps/atocal/contacts/search	Contact search for the invitee input

Link parameters (GET /confirm and form POST /create)

Parameter	Required	Rules
summary	yes	max 255 chars
start	yes	datetime-local, e.g. 2026-10-07T14:15
end	yes	after start, same format
description	no	max 10000 chars
location	no	HTTPS URL
url	no	HTTPS URL; merged into description
organizer	no	email address; display info only

The create form adds calendarId (selected calendar) and attendees (emails, max 20).

Dates carry no timezone and are interpreted in the user's Nextcloud timezone (server default as fallback).

Organizer

The event's ICS ORGANIZER is the Nextcloud user's own email address. Invitations to attendees are scheduled by the CalDAV backend in the calendar owner's name, which only works when the organizer matches the owner.

The organizer link parameter is shown on the confirm page as meeting information and is used as ORGANIZER fallback only when the user has no profile email — in that case no working invitations may be sent, so profile emails should be set.

Reminder

Every created event gets a display alarm 15 minutes before it starts (TRIGGER:-PT15M VALARM). The reminder is not configurable.

Example:

https://cloud.example.com/apps/atocal/confirm?summary=Kickoff&start=2026-10-12T10:00&end=2026-10-12T11:00&location=https%3A%2F%2Fmeet.example.com%2Fkickoff

Requirements

• Nextcloud 34 or 35
• Calendar app enabled
• A writable calendar ("Personal" is preselected if present)

Install

Copy this directory to the Nextcloud server as apps/atocal, then:

occ app:enable atocal

Structure

appinfo/info.xml                        app metadata
appinfo/routes.php                      routes
css/style.css                           page styles
js/invitees.js                          invitee input
l10n/*.json                             translations
lib/AppInfo/Application.php             container setup
lib/Controller/CalendarController.php   confirm/create logic
templates/confirm.php                   confirmation page

Licence

AGPL-3.0-or-later, see LICENSE. AToCal comes without any warranty.

AToCal is an independent project and is not affiliated with any other product or company of a similar name.