Blog · Use case
Share calendar availability without showing event details
Coordinating at home needs one fact from each calendar: free or busy. Sivella syncs availability from Google, Outlook, iCloud and CalDAV and never exposes what an event is, so the household can find a workable evening without anyone reading anyone else's diary.
The usual advice for households is to keep one calendar together. It is good advice that almost nobody follows, for reasons that are not laziness.
Your calendar has work in it. It has a first-round interview you have told nobody about, a therapist, a scan, a call with a lawyer, a surprise you are organising for the person you would be sharing it with. Handing over the whole thing to solve "which night are we both free" is a wildly disproportionate trade, so people keep their calendars and coordinate by asking instead.
Free or busy is nearly always the whole question
Watch what a household actually needs from a calendar and it is thinner than it looks. Can you take the car in on Wednesday. Is anyone around when the delivery comes. When could four of us eat together this week. Every one of those resolves against blocks of time, not against what fills them.
The detail is what makes calendar sharing feel invasive, and it is the part nobody needed. Sivella's calendar sync carries availability only and never exposes event details, which turns the decision from "do I trust you with my diary" into "do you mind the house knowing Wednesday afternoon is gone".
Everyone keeps the calendar they already use
Households do not run on one platform. Work is on Outlook, a phone is on iCloud, somebody's side project is on Google, and the one person who self-hosts is on CalDAV. Any approach that requires everybody to move is dead before it starts.
Sivella reads availability from Google, Outlook, iCloud and CalDAV. Nobody migrates, nobody maintains a duplicate household calendar by hand, and the sync keeps working when someone's work IT changes something, because the calendar of record stays where it was.
What it changes about the asking
The small tax this removes is the round trip. "Are you free Thursday?" costs one message, a wait of unknown length, a reply that is qualified, and a follow-up. Do it three times a week and it is a meaningful part of how the two of you talk to each other, spent on logistics.
With availability visible, the question is already answered when you go looking, and what remains is the actual decision. It also makes the invisible obvious: the reason one person has done every weekday errand for a month is usually sitting plainly in the shape of two calendars, and neither of you had a way to see it side by side.
Where the line sits
Availability is shared with the household. The content of an event is not, and there is no view that quietly reveals it. If you want the house to know what something is, you say so, by putting it in Sivella as a task, a reminder or a decision.
That is the right default for people who live together. The information a home needs to run is not the same information a person keeps private, and a tool that conflates them will be used carefully, incompletely, or not at all.