Your availability, in sync.
Your meeting details, untouched.
Avenclave is a privacy-preserving, local-first Windows app for people who run more than one professional calendar. It keeps every calendar honest about when you are busy, and it does that without copying titles, attendees, or notes, and without asking anyone’s IT administrator for permission.
Windows desktop. Microsoft 365 and Google Workspace. Not yet available to download. See where the product stands.
- Your real meeting. Stays where you booked it.
- Placeholder on the other calendar. Same time, no title, no attendees, no notes.
One person, several calendars, no shared truth.
Consultants, fractional executives, contractors, advisors, and board members end up holding a separate calendar for every organization they work with. None of those calendars can see the others, so the only thing keeping them consistent is you, manually blocking time and hoping you did not miss one.
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Double bookings you find out about late
A client books the slot your other client already took, because their calendar had no reason to think you were busy.
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Manual blocking that never stays correct
Copying holds by hand works until the first meeting moves. Then every copy is quietly wrong and nothing tells you.
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Sharing more than you meant to
The obvious fixes tend to involve handing one organization visibility into another one’s meetings, which is usually not yours to give.
It synchronizes availability, not calendars.
Avenclave is not trying to merge your calendars. It is making sure each one can answer a single question correctly: are you free at this time?
- 01
Connect each calendar
Sign in to each Microsoft 365 or Google Workspace account through that provider’s own sign-in. Pick which calendar on each account Avenclave is allowed to read.
- 02
Avenclave reads only availability
It looks at when you are busy inside a rolling window you choose, and turns that into a plain timeline of intervals. Free and Working Elsewhere are ignored by default.
- 03
Placeholders appear on the others
Each of your other calendars gets a privacy-safe placeholder at the same absolute time. Move or cancel the real meeting and the placeholder follows, or disappears.
Exactly what crosses between calendars.
This is the whole list. It is short on purpose: a placeholder exists to occupy time, not to describe anything.
What Avenclave writes
- Start time and end time, in absolute terms across time zones
- Whether that period should read as busy or tentative
- A placeholder label you choose, which never derives from the real meeting
- An internal identifier that lets Avenclave recognize its own placeholder later
What Avenclave never reads across
- Meeting titles and subjects
- Attendees, organizers, and their addresses
- Descriptions, agendas, and notes
- Locations, links, and dial-in details
- Attachments and files
- Anything at all from a calendar you did not select
Four commitments the design has to keep.
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Local-first
Avenclave runs on your Windows desktop and talks to your calendars directly. There is no Avenclave account, no Avenclave server, and no copy of your schedule in the middle.
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Data-minimizing
A placeholder carries a start time, an end time, and a label you choose. Titles, attendees, notes, locations, and attachments never leave the calendar they belong to.
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No tenant-wide consent
Avenclave signs in the way you already do, through each provider’s own sign-in. It asks for no elevated permissions and no organization-wide approval.
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Fail-closed
When Avenclave cannot prove that a placeholder is its own, it changes nothing and tells you so. Uncertainty is never reported as success.
You should be able to forget it is running.
After the first pass, Avenclave keeps checking on a schedule you set: about every five minutes if you want changes reflected quickly, roughly hourly if you would rather it stay out of the way, or a balanced setting in between. Healthy operation produces no notifications, no badges, and no animation.
Your providers and your organization decide how long a sign-in stays valid, and some policies require it as often as once a day. When that happens Avenclave stops writing, brings up that provider’s own sign-in, confirms the restored account is still the same one, and resumes. We would rather tell you that than promise you will never see a sign-in prompt again.
How Avenclave reports itself
States are named plainly, and an ambiguous result is never dressed up as a good one.
- Synced
- The placeholder was confirmed against fresh calendar state.
- Pending
- A change is recorded and on its way. Nothing is lost if the app restarts.
- Inconclusive
- Avenclave could not prove ownership, so it made no change and said so.
- Action required
- A calendar needs you to sign in again before it can continue.
Want to know when Avenclave is ready?
There is no signup form and no tracking. Send one email and we will reply once there is something real to try. Nothing else happens to your address.
We will not add you to a mailing list, and we will not share your address.