# Plans and limits

Subscribe calendars are available on every plan. On Free you test with sandbox calendars; live calendars for the public start with Basic.

| Plan | Subscribe calendars |
|---|---|
| **Free** | Sandbox only: up to 3 test calendars with 500 events each |
| **Basic** | 1 live calendar, up to 500 active subscribers |
| **Professional** | 10 live calendars, up to 5,000 active subscribers |
| **Beyond that** | on request |

In addition, every live calendar holds **up to 5,000 events**. A recurring series counts as one event.

Prices and all other plan features: [kalender-sync.de/en/pricing](https://kalender-sync.de/en/pricing/).

## What is an active subscriber?

A subscriber is **active** while their calendar app fetched the feed in the last 14 days. The number covers all live calendars of your account together. Sandbox calendars don't count. → [Statistics](https://docs.kalender-sync.de/en/abo-kalender/statistik/)

## Sandbox and live

- **Sandbox calendars** are created with a sandbox key (starts with `ks_test_`). They work in real calendar apps but carry `[TEST]` in their name and a "Test calendar" note on the subscribe page. Ideal for setting up a plugin or building an integration.
- **Live calendars** are created with a live key (starts with `ks_live_`). Live keys start with Basic.
- **Consent before the first live calendar:** under **Settings › Developer / API** you agree once to the [additional terms for subscribe calendars](https://kalender-sync.de/en/terms/#subscribe-calendars) and the [DPA addendum](https://kalender-sync.de/en/dpa/), then you can create the live key. The sandbox never needs consent.

A calendar is created as either a sandbox or a live calendar. It cannot be switched.

In API responses the Professional plan is still called `business`, for example `"plan": "business"`.

Sandbox and live data are strictly separate: a sandbox key only sees sandbox calendars, a live key only live calendars.

## What happens when you reach a limit?

- **Active subscribers:** everything keeps running. No subscription is switched off, and new subscribers can still join. You get an email and a notice in the statistics so we can find a fitting plan together.
- **Number of live calendars:** you can create another calendar after deleting one or moving to a larger plan.
- **Events per calendar:** new events are refused until you delete old ones. Existing events can still be changed.

## After a downgrade or after the trial

If your account has more live calendars than your plan covers, your subscribers keep getting every event. The calendars only accept changes again after you upgrade or delete a calendar. Sandbox calendars are never affected.