Dynamic Links

A Dynamic Link generates an add-to-calendar redirect from query parameters. You build the link with event details and a calendar service, and when someone clicks it they are sent straight to that calendar with the event pre-filled. Nothing is stored on AddCal.

Create a Dynamic Link Key Full API reference

Supported calendar services

Set service to any of the values below. The visitor is redirected straight to that calendar with the event pre-filled, no account or extra step required.

Google Calendar

service=google

Apple Calendar

service=apple

Outlook desktop

service=outlook

Outlook.com

service=outlook_web

Office 365

service=office365

Yahoo Calendar

service=yahoo

Download .ics

service=ics

AddEvent compatibility mode

Migrating from AddEvent? There is a drop-in compatible endpoint at /api/dyn_ade that accepts AddEvent's parameter names, so your existing links keep working. Use client in place of uid, and AddEvent service values like outlookcom and stream are mapped automatically.

AddEvent-compatible link

https://addcal.co/api/dyn_ade
  ?client=dk_abc123
  &service=outlookcom
  &title=Team+Standup
  &start=2026-06-15T14:00:00
  &timezone=America/New_York

Everything else, recurrence, reminders, all the same parameters, works exactly as it does on the standard endpoint.

Dynamic Links vs Smart Links

Both create calendar events from a URL, but they do different jobs.

Smart Links create and store an event in your AddCal calendar, with tracking, dedup, and optional approval. Best when you want the event to live in AddCal.
Dynamic Links generate a one-off redirect straight to the visitor's calendar app. Nothing is stored. Best for high-volume add-to-calendar links in emails and apps, with recurrence and reminders.

Dynamic Links require a Dynamic Link Key and are available on the Business plan.

The link

Build a link to /api/dyn with your event details as query parameters, then put it wherever your audience is, an email, a button, an app. When someone clicks it, they are redirected straight to their chosen calendar with the event pre-filled.

Dynamic Link

https://addcal.co/api/dyn
  ?uid=dk_abc123
  &service=google
  &title=Team+Standup
  &start=2026-06-15T14:00:00
  &duration=30
  &timezone=America/New_York
  &recurring=FREQ=WEEKLY;BYDAY=MO,WE,FR
  &alarm=15

Parameters

Pass event details as query parameters. A key, a service, a title, and a start are required.

Parameter	Required	Description
`uid`	Required	Your Dynamic Link Key, for example dk_abc123. Create one in your dashboard on the Business plan.
`service`	Required	Where to redirect: google, apple, outlook, outlook_web, office365, yahoo, or ics.
`title`	Required	Event title, up to 255 characters.
`start`	Required	Start date and time in ISO 8601 format, for example 2026-06-15T14:00:00.
`end`	Optional	End date and time in ISO 8601. Defaults to one hour after start if omitted.
`duration`	Optional	Duration in minutes. Takes precedence over end.
`timezone`	Optional	IANA timezone, required for timed events, for example America/New_York.
`all_day_event`	Optional	Set to true for an all-day event.
`description`	Optional	Event description, up to 2000 characters.
`location`	Optional	Physical address or virtual meeting URL, up to 255 characters.
`alarm`	Optional	Reminder in minutes before the event, for example 15.
`recurring`	Optional	An RFC 5545 recurrence rule (RRULE), for example FREQ=WEEKLY;BYDAY=MO,WE,FR.
`transp`	Optional	Busy status: OPAQUE (busy) or TRANSPARENT (free). Defaults to OPAQUE.

Recurrence and reminders

Unlike Smart Links, Dynamic Links accept an RFC 5545 recurrence rule via recurring and a reminder via alarm, so the event lands in the calendar already set to repeat with a reminder attached.

Use transp=TRANSPARENT to add the event as free time rather than busy.